Before you spearfish — this comes first
- Get proper instruction before you spearfish. A recognised freediving or spearfishing course teaches the things that actually kill people in this sport, and reading about them is not the same as being taught them.
- Dive with a buddy, and dive one up, one down — one diver in the water, one on the surface watching them, every dive. A breath-hold blackout is silent and gives no warning; a watching buddy is the difference between an incident and a fatality.
- Stay inside your own training and experience. Depth and breath-hold times are personal, they change day to day, and nobody else's numbers apply to you.
- Understand the conditions before you enter the water: visibility, current, swell, tide, boat traffic and your exit. Conditions decide whether a dive is reasonable far more often than skill does.
- Use equipment you have been shown how to use, check it before every session, and be visible — a marked float and line are how boat traffic knows you are there.
- Never extend a dive for a fish. No catch is worth pushing a breath-hold, and the urge to take one more second is exactly what a blackout feels like from the inside — which is to say, like nothing at all.
Dive floats and float lines
Tackle · Last reviewed 2026-08-10
The marked surface float and its line — the piece of spearfishing equipment most often thought of as a convenience, and actually the primary means of not being run over.
Safety
Boat traffic and being seen — Can cause serious injury or death
Without a marked float, a diver is invisible to boat traffic. Propeller injuries to divers are catastrophic and frequently fatal, and the helmsman usually never knows anybody was there.
What reduces it: Always dive with a conspicuous, flagged surface float, kept close rather than trailing far behind. Avoid navigation channels and moorings. Look up before surfacing and surface with an arm raised.
Entanglement — Can cause serious injury or death
The float line is the most likely thing to entangle a diver, particularly in swell, around structure, or with excess line in the water. Entanglement during a breath-hold is a time-limited emergency.
What reduces it: Keep the line no longer than needed, keep it tidy, carry a knife reachable with either hand, and never dive alone.
Precautions that always apply here
- Never spearfish or freedive alone.
- Dive one up, one down: one diver down, one on the surface actively watching, every single dive.
- Carry a charged phone in a waterproof case, or another means of calling for help.
A dive float is a buoyant, conspicuously marked object on the surface, attached to the diver by a line. It does three things, and only one of them is about fish.
It marks the diver's position to boat traffic. A freediver at or just under the surface is functionally invisible from a boat, and a marked float carrying a recognised dive flag is the only reliable way for a helmsman to know somebody is there. That is its most important function by a wide margin.
It gives a shot fish something to fight against other than the diver, which means the diver can let go of the gun and surface — the correct action if a fish is going to take longer to deal with than the breath allows.
And it provides a place to secure catch and a fixed reference on the surface to return to and rest against.
The float line is the part that requires care. It connects the diver to the float and, in doing so, becomes the most likely thing to entangle them.
- Category
- Spearfishing equipment
What it does
Marks the diver's position on the surface to boat traffic; provides buoyancy to rest on and to secure catch to; absorbs the effort of a shot fish so the diver does not have to; and gives a fixed surface reference for orientation and for the buddy watching.
How to choose one
- Choose a float that is conspicuous — bright, large enough to be seen in a chop, and carrying a recognised dive flag.
- Keep the float line no longer than the depth you are actually diving; excess line in the water is entanglement waiting to happen.
- Use a line that is visible and manageable rather than the thinnest available.
- Have a means of releasing yourself from the line quickly, and know where it is by feel.
- The float is safety equipment. Choose it before choosing the gun.
What the numbers mean
BUOYANCY, in kilograms, is how much the float can support — it must handle the largest fish you might attach plus a resting diver. LINE LENGTH should match the depth range being dived, with a margin, and no more. LINE TYPE varies from bungee, which absorbs the shock of a fish, to static line, which gives more direct feel. FLAG: the flag flown determines what a passing helmsman is legally required to do, and which flag is recognised and what distance vessels must keep varies by country — check locally rather than assuming.
Care, and how it fails
Floats lose air or take on water and stop supporting what they are rated for; check buoyancy periodically rather than assuming. Lines abrade against rock and against the boat and should be inspected along their length. Faded flags stop being visible, which defeats the entire purpose — replace them. Rinse everything after every dive.
The float does three jobs and only one of them is about fish
A dive float looks like fishing equipment and is mostly safety equipment.
FIRST, IT MARKS A PERSON IN TRAFFIC. A diver at the surface is almost invisible from a boat: low, dark, intermittent and small against chop. A float with a dive flag is the only reliable statement that somebody is in the water, and boat strike is one of the most consequential hazards in the whole activity. This is the job that does not depend on catching anything.
SECOND, IT TAKES THE FIGHT. On a breakaway rig the shot fish is attached to the float rather than to the diver, which is the only arrangement that works on fish large enough to pull a person, and which lets a diver surface and breathe while the fish tires.
THIRD, IT CARRIES THINGS. Catch, spare gear, water — and crucially it carries them away from the diver's body, which is the whole argument of the stringers record: fish blood and vibration belong at the end of a line and not on a belt.
THE FLOAT LINE IS THE PART THAT IS DANGEROUS. It is a rope through the water column with a person at one end, and it entangles divers. Length is a genuine trade: long enough to reach the surface from the working depth with margin, short enough that there is not a great deal of slack rope in the water. Bungee sections absorb the shock of a running fish and reduce the length of static line, which is why they are common on the heavier rigs.
AND EVERY ONE OF THESE JOBS ASSUMES A KNIFE. A diver attached to a float line must be able to cut themselves free with either hand, at depth, without looking, and that requirement is why the cutting tool is equipment rather than an accessory.
WHAT FISHINGHQ WILL NOT TELL YOU is whether a flag is required where you are diving, what it must look like, or how far a boat must stay from it. Those differ by country and by water and are revised; the authority for the water is the place to ask, and it is worth asking before the first dive rather than after an incident.
Authoritative guidance
Stated by a fisheries authority, scientific institute or recognised angling body. Authoritative, but summarising rather than demonstrating.
- CMAS technical and sporting standards for underwater activities — Confédération Mondiale des Activités Subaquatiques (Standards body)Relied on for: Breath-hold spearfishing practice, equipment convention and the safety expectations set out by the international underwater federation.States this directlyCitation checked — the work exists and is described correctly
- DAN guidance on freediving safety, hypoxia and shallow-water blackout — Divers Alert Network (Water-safety or diver-training authority)Relied on for: Freediving safety guidance including the buddy system, weighting, positive buoyancy at the surface and the management of equipment failure.States this directlyPassage read and verified
- BlueWater Hunting and Freediving — BlueWater Freedivers, Ventura, California, 1995 (Practitioner report)Relied on for: Spearfishing equipment and practice: gun and rigging choice, shot placement, and the handling of a shot fish, from a practitioner tradition distinct from the European one.States this directlyCitation checked — the work exists and is described correctly
Where to go next
Where it is used
- Blue-water spearfishingA float and breakaway rather than a reel, and not as a preference: blue-water quarry is large enough to tow a diver, so the only arrangement that works is putting the fish on a buoy at the surface.
- SpearfishingHunting fish underwater on a single breath, using a speargun or pole spear — the most selective way of taking a fish, and the most demanding of the person doing it.
What these connections rest on (2)
Practitioner consensus — 1 connection
Widely and independently recommended by experienced anglers and specialist sources. This is real angling knowledge, not proof: controlled evidence for it is limited, and FishingHQ records it as convention rather than as a demonstrated effect.
Blue-water spearfishing
A dependency between a discipline and the rigging its quarry size forces. The alternative is dangerous rather than merely less effective.
- CMAS technical and sporting standards for underwater activities — Confédération Mondiale des Activités Subaquatiques (Standards body)Relied on for: Breath-hold spearfishing practice, equipment convention and the safety expectations set out by the international underwater federation.States this directlyCitation checked — the work exists and is described correctly
- BlueWater Hunting and Freediving — BlueWater Freedivers, Ventura, California, 1995 (Practitioner report)Relied on for: Spearfishing equipment and practice: gun, shaft, tip and rigging choice, and the handling of a shot fish, from a practitioner tradition distinct from the European one.States this directlyCitation checked — the work exists and is described correctly
Authoritative guidance — 1 connection
Stated by a fisheries authority, scientific institute or recognised angling body. Authoritative, but summarising rather than demonstrating.
Spearfishing
Categorical placement, and the float is safety equipment as much as fishing equipment.
- BSAC diving safety guidance and annual incident report — British Sub-Aqua Club (Water-safety or diver-training authority)Relied on for: Surface marking practice for divers.States this directlyCitation checked — the work exists and is described correctly
What it works with
- Catch handling and transportThe float carries the catch, which is the point of the stringer argument: fish blood and vibration belong at the end of a line rather than on a belt.
- Shooting line and breakaway riggingA float only takes the fight if the shooting line detaches from the gun at the shot. Breakaway rigging is what makes the float part of the system rather than an accessory tied to it.
What these connections rest on (2)
Practitioner consensus — 2 connections
Widely and independently recommended by experienced anglers and specialist sources. This is real angling knowledge, not proof: controlled evidence for it is limited, and FishingHQ records it as convention rather than as a demonstrated effect.
Catch handling and transport
A dependency between equipment, recorded because choosing one of these constrains the other. Convention, recorded as convention.
- CMAS technical and sporting standards for underwater activities — Confédération Mondiale des Activités Subaquatiques (Standards body)Relied on for: Breath-hold spearfishing practice, equipment convention and the safety expectations set out by the international underwater federation.States this directlyCitation checked — the work exists and is described correctly
- BlueWater Hunting and Freediving — BlueWater Freedivers, Ventura, California, 1995 (Practitioner report)Relied on for: Spearfishing equipment and practice: gun, shaft, tip and rigging choice, and the handling of a shot fish, from a practitioner tradition distinct from the European one.States this directlyCitation checked — the work exists and is described correctly
Shooting line and breakaway rigging
A dependency between equipment, recorded because choosing one of these constrains the other. Convention, recorded as convention.
- CMAS technical and sporting standards for underwater activities — Confédération Mondiale des Activités Subaquatiques (Standards body)Relied on for: Breath-hold spearfishing practice, equipment convention and the safety expectations set out by the international underwater federation.States this directlyCitation checked — the work exists and is described correctly
- BlueWater Hunting and Freediving — BlueWater Freedivers, Ventura, California, 1995 (Practitioner report)Relied on for: Spearfishing equipment and practice: gun, shaft, tip and rigging choice, and the handling of a shot fish, from a practitioner tradition distinct from the European one.States this directlyCitation checked — the work exists and is described correctly
Understanding it
- Line and float-line tanglesThe float line is one of the diver's own entanglement sources and is managed rather than merely attached.
- Boat traffic, and being seen from the surfaceA float is the only thing about a diver that a helmsman can realistically see.
- Entanglement, and the knife that is not a weaponThe float line is one of the diver's own entanglement sources and is managed rather than merely attached.
- What order to buy equipment inA float is bought before a gun because a diver at the surface is otherwise invisible to boats.
What these connections rest on (4)
Authoritative guidance — 4 connections
Stated by a fisheries authority, scientific institute or recognised angling body. Authoritative, but summarising rather than demonstrating.
Line and float-line tangles
The equipment that causes the problem it also solves.
- BSAC diving safety guidance and annual incident report — British Sub-Aqua Club (Water-safety or diver-training authority)Relied on for: Diving safety guidance on entanglement hazards, line management and emergency cutting equipment.States this directlyCitation checked — the work exists and is described correctly
Boat traffic, and being seen from the surface
The float's primary function is visibility rather than fishing.
- BSAC diving safety guidance and annual incident report — British Sub-Aqua Club (Water-safety or diver-training authority)Relied on for: Diving safety guidance on surface marking, dive flags and vessel traffic.States this directlyCitation checked — the work exists and is described correctly
Entanglement, and the knife that is not a weapon
The equipment that most often causes the problem it also solves.
- BSAC diving safety guidance and annual incident report — British Sub-Aqua Club (Water-safety or diver-training authority)Relied on for: Diving safety guidance on entanglement hazards and emergency cutting equipment.States this directlyCitation checked — the work exists and is described correctly
What order to buy equipment in
Safety equipment ordered ahead of fishing equipment.
- BSAC diving safety guidance and annual incident report — British Sub-Aqua Club (Water-safety or diver-training authority)Relied on for: Diving equipment guidance including exposure protection, weighting and surface marking.States this directlyCitation checked — the work exists and is described correctly
Practitioner consensus — 1 connection
Widely and independently recommended by experienced anglers and specialist sources. This is real angling knowledge, not proof: controlled evidence for it is limited, and FishingHQ records it as convention rather than as a demonstrated effect.
Line and float-line tangles
An explainer carrying a mechanism the equipment record depends on.
- CMAS technical and sporting standards for underwater activities — Confédération Mondiale des Activités Subaquatiques (Standards body)Relied on for: Breath-hold spearfishing practice, equipment convention and the safety expectations set out by the international underwater federation.States this directlyCitation checked — the work exists and is described correctly
- BlueWater Hunting and Freediving — BlueWater Freedivers, Ventura, California, 1995 (Practitioner report)Relied on for: Spearfishing equipment and practice: gun, shaft, tip and rigging choice, and the handling of a shot fish, from a practitioner tradition distinct from the European one.States this directlyCitation checked — the work exists and is described correctly
Instead of this
- Surface marking and signallingThe float carries the flag, and marking a diver for boat traffic is the job the float does whether or not anything is caught. Boat strike is one of the most consequential hazards in the activity and it does not care how the fishing is going.
- Reels, float lines and breakaway systemsThe float marks the diver for boats and holds the catch away from the body, independent of any fish.
- Speargun reelsThe two answers to the same problem — a shot fish has to be attached to something that yields — and they fail in opposite directions. A reel keeps everything on the gun and attaches the DIVER to the fish; a float takes the fight and puts a rope in the water column.
- Weighting and quick releaseThe two things that decide whether an unconscious diver's airway is out of the water: ballast that comes off, and something that floats. Neither substitutes for the other and neither substitutes for a buddy who is watching.
What these connections rest on (4)
Authoritative guidance — 2 connections
Stated by a fisheries authority, scientific institute or recognised angling body. Authoritative, but summarising rather than demonstrating.
Surface marking and signalling
Diving body guidance treats marking and signalling as separate measures.
- BSAC diving safety guidance and annual incident report — British Sub-Aqua Club (Water-safety or diver-training authority)Relied on for: Guidance on surface marking and on signalling for assistance.States this directlyCitation checked — the work exists and is described correctly
Reels, float lines and breakaway systems
The float's safety functions apply on a session where nothing is shot.
- BSAC diving safety guidance and annual incident report — British Sub-Aqua Club (Water-safety or diver-training authority)Relied on for: Diving safety guidance on surface marking, dive flags and diver visibility.States this directlyCitation checked — the work exists and is described correctly
Practitioner consensus — 3 connections
Widely and independently recommended by experienced anglers and specialist sources. This is real angling knowledge, not proof: controlled evidence for it is limited, and FishingHQ records it as convention rather than as a demonstrated effect.
Surface marking and signalling
A dependency between equipment, recorded because choosing one of these constrains the other. Convention, recorded as convention.
- DAN guidance on freediving safety, hypoxia and shallow-water blackout — Divers Alert Network (Water-safety or diver-training authority)Relied on for: Freediving safety guidance including weighting, positive buoyancy at the surface, the buddy system and the management of entanglement and equipment failure.States this directlyPassage read and verified
- CMAS technical and sporting standards for underwater activities — Confédération Mondiale des Activités Subaquatiques (Standards body)Relied on for: Breath-hold diving safety practice and equipment expectations set out by the international underwater federation.States this directlyCitation checked — the work exists and is described correctly
Speargun reels
A comparison a diver is genuinely choosing between, joining two records that resolve one another.
- CMAS technical and sporting standards for underwater activities — Confédération Mondiale des Activités Subaquatiques (Standards body)Relied on for: Breath-hold spearfishing practice, equipment convention and the safety expectations set out by the international underwater federation.States this directlyCitation checked — the work exists and is described correctly
- BlueWater Hunting and Freediving — BlueWater Freedivers, Ventura, California, 1995 (Practitioner report)Relied on for: Spearfishing equipment and practice: gun, shaft, tip and rigging choice, and the handling of a shot fish, from a practitioner tradition distinct from the European one.States this directlyCitation checked — the work exists and is described correctly
Weighting and quick release
A comparison a diver is genuinely choosing between, joining two records that resolve one another.
- DAN guidance on freediving safety, hypoxia and shallow-water blackout — Divers Alert Network (Water-safety or diver-training authority)Relied on for: Freediving safety guidance including weighting, positive buoyancy at the surface, the buddy system and the management of entanglement and equipment failure.States this directlyPassage read and verified
- CMAS technical and sporting standards for underwater activities — Confédération Mondiale des Activités Subaquatiques (Standards body)Relied on for: Breath-hold diving safety practice and equipment expectations set out by the international underwater federation.States this directlyCitation checked — the work exists and is described correctly
Safety reading
- Entanglement while breath-hold divingA float line is a rope through the water column with a person at one end. Length is a genuine trade between reaching the surface with margin and leaving slack rope where a diver is working.
- Surface markers and boat trafficA diver at the surface is low, dark, intermittent and small against chop, and a marked float is the only reliable statement that somebody is in the water.
What these connections rest on (2)
Authoritative guidance — 2 connections
Stated by a fisheries authority, scientific institute or recognised angling body. Authoritative, but summarising rather than demonstrating.
Entanglement while breath-hold diving
Freediving body guidance on entanglement while breath-holding.
- DAN guidance on freediving safety, hypoxia and shallow-water blackout — Divers Alert Network (Water-safety or diver-training authority)Relied on for: Guidance on entanglement hazards for breath-hold divers.States this directlyPassage read and verified
A link to a safety topic substantial enough to be read in full.
- DAN guidance on freediving safety, hypoxia and shallow-water blackout — Divers Alert Network (Water-safety or diver-training authority)Relied on for: Freediving safety guidance including weighting, positive buoyancy at the surface, the buddy system and the management of entanglement and equipment failure.States this directlyPassage read and verified
- CMAS technical and sporting standards for underwater activities — Confédération Mondiale des Activités Subaquatiques (Standards body)Relied on for: Breath-hold diving safety practice and equipment expectations set out by the international underwater federation.States this directlyCitation checked — the work exists and is described correctly
Surface markers and boat traffic
Diving body guidance on surface marking and boat traffic.
- BSAC diving safety guidance and annual incident report — British Sub-Aqua Club (Water-safety or diver-training authority)Relied on for: Guidance on surface marker buoys and visibility to surface traffic.States this directlyCitation checked — the work exists and is described correctly
A link to a safety topic substantial enough to be read in full.
- DAN guidance on freediving safety, hypoxia and shallow-water blackout — Divers Alert Network (Water-safety or diver-training authority)Relied on for: Freediving safety guidance including weighting, positive buoyancy at the surface, the buddy system and the management of entanglement and equipment failure.States this directlyPassage read and verified
- CMAS technical and sporting standards for underwater activities — Confédération Mondiale des Activités Subaquatiques (Standards body)Relied on for: Breath-hold diving safety practice and equipment expectations set out by the international underwater federation.States this directlyCitation checked — the work exists and is described correctly
Check the rules before you fish
Fishing laws, bylaws, access rules, seasons, bait restrictions and permitted methods vary by location and can change. Check the current rules from the relevant authority and the water you intend to fish before fishing.
Check with:
- Current national or regional law for where you are fishing
- Current local bylaws
- The relevant fisheries authority
- The landowner, club or fishery whose water it is
- Any restrictions specific to the species or the method you intend to use
Sources for this page
- BSAC diving safety guidance and annual incident report — British Sub-Aqua Club (Water-safety or diver-training authority)Relied on for: Surface marking and buddy practice for divers, and the visibility problem divers present to vessels.States this directlyCitation checked — the work exists and is described correctly
How FishingHQ labels evidence is explained in the evidence policy.