Sunglasses straps and retainers: the four types, and which one suits what you are doing

A retainer is the cheapest insurance available for an expensive pair of sunglasses, and the type you need depends entirely on whether the risk is losing them, dropping them, or having them slide down your face. Those are three different problems and the strap aisle treats them as one.

Here is what each kind actually does.

1. The thin cord

The classic: a slim braided or leather cord with rubber or silicone loops at each end that slip over the temple tips.

What it is for: keeping a pair accessible rather than secure. You take them off, they hang on your chest, you do not put them down on a table and leave them there. Most losses are not dramatic — they are a pair left behind somewhere — and a cord solves that.

What it is not for: floating. A thin cord adds almost no buoyancy. Sunglasses with a thin cord sink at very nearly the same rate as sunglasses without one.

The catch: a hanging pair swings and knocks against whatever you lean over. It is a storage position, not a safe one. And as our storage piece notes, hanging from one point puts a twisting load on the hinge.

2. The neoprene float strap

A wide, flat neoprene sleeve that slides over the temples and sits behind your head.

What it is for: water. This is the only common retainer that genuinely floats a pair of sunglasses, because neoprene is a closed-cell foam with real buoyancy and there is enough of it.

If you fish, sail, kayak or paddleboard, this is the one. The difference between a pair you retrieve and a pair you watch sink is a few grams of foam. Our sailing and kayaking guide makes the same point about the strap mattering more than the lens for anyone leaning over the side.

Test it before you trust it. Float capacity depends on the strap's size and your frame's weight. Drop the pair in a sink. A heavy frame with a small strap still sinks, slowly, which is worse than useless because you will believe it floats.

The catch: bulky, warm, and it holds salt water against your neck. Fine on a boat, unpleasant on a city street.

3. Silicone temple grips

Small silicone sleeves that slide onto the arm just before the bend behind your ear, adding grip against your skin.

What it is for: stopping slipping, without a cord. They work by friction where the frame already touches you, rather than by tethering it.

This is the quiet option and the most underrated. For running, cycling, hiking and hot weather generally — anywhere sweat is the problem rather than water — grips solve the actual complaint without anything round your neck. Our running guide covers the broader fit question.

The catch: they do nothing if the pair comes off entirely. They are grip, not retention.

4. The adjustable sports cord

A cord or strap with a toggle that tightens behind the head, pulling the frame snug.

What it is for: keeping the frame firmly on during motion — mountain biking, climbing, anything with impact or inversion.

Tightened properly the frame stays put through a lot. That is the point.

The catch: over-tightening pulls the arms inward and, over months, bends them. It also presses the frame harder into your nose and temples, which is uncomfortable and can cause the kind of headache we describe in why sunglasses give me a headache. Snug, not tight.

Fitting a retainer without wrecking the frame

A detail almost nobody is told, and it matters.

The loop goes on the very tip of the temple, not pushed up the arm.

If you push the loop several centimetres up the arm, the cord pulls from a point well forward of the end. That creates leverage against the hinge every time the cord takes load. Over time it loosens the hinge and can splay the arm — producing exactly the slipping problem you bought the retainer to fix.

On the tip, the load pulls straight back along the arm's axis, where the frame is strongest.

Two more fitting points:

Match the loop to the arm thickness. A loop too loose slips off; one forced onto a thick arm stretches and tears within weeks.

Check the length. The pair should sit comfortably at your collarbone when hanging, not swinging at your stomach.

When a retainer is the wrong fix

Worth saying plainly, because it is the most common misuse.

If your sunglasses slip down your nose constantly, a cord is a patch over a fit problem. The underlying cause is usually a frame too narrow for your face, splayed arms, or a bridge that does not match your nose. A cord stops you losing them; it does not stop the sliding, and you will spend the day pushing them up anyway.

Our slipping sunglasses piece covers the three real causes, and how should sunglasses fit has the check that identifies which one you have. Fix the fit; add the retainer for the risk that remains.

Which to own

Most people need one, some people need two.

Water of any kind: neoprene float strap, tested in a sink.

Running, cycling, hot weather: silicone temple grips.

General outdoor life, travel, putting them down a lot: thin cord.

High-motion sport: adjustable cord, snug not tight.

A float strap and a set of grips covers almost everything between them, for less than the price of one replacement lens.

Materials, and how long each lasts

Retainers are consumables and the material decides how quickly.

Silicone resists UV and salt well, stays flexible in cold, and grips better when damp. The best choice for anything involving water or sweat. It picks up dust and lint, which is cosmetic.

Neoprene floats, insulates and is comfortable against the neck. It absorbs water and holds it, which means salt sits against your skin and against the strap's own stitching. Rinse it.

Natural rubber perishes. It hardens, cracks and goes sticky with UV and skin oil, usually within a season or two of regular outdoor use. Cheap, and it shows.

Braided cord and leather are durable and look good. Leather suffers badly in salt water and should stay away from boats.

Waxed cotton sits in between: tougher than it looks, not waterproof.

Keeping them clean

Retainers sit against your neck collecting sweat, sunscreen and salt, and almost nobody washes them.

The consequence is not just unpleasant. Salt and sunscreen residue transfers from the strap onto the temple tips and from there to the lenses, which is one reason beach sunglasses develop a film that resists cleaning. Sunscreen is particularly hard on coatings, as our cleaning guide explains.

Warm water, a drop of mild detergent, rinse thoroughly, air dry away from direct sun. Neoprene straps need squeezing out rather than wringing, which distorts the foam. Do it at the end of a trip, not at the start of the next one.

A note on children

Worth separating, because the requirement is different.

For children the retainer is not about losing an expensive pair — it is about the pair staying on at all. Small heads, constant motion, and no habit of pushing frames back up.

An adjustable band rather than a cord is the right answer: it holds the frame on rather than catching it afterwards, and a cord around a small child's neck is a hazard rather than a convenience. Most children's eyewear ships with one, and our kids' sunglasses piece covers what else to look for.

Frequently asked questions

The short version

Thin cords keep a pair with you. Only neoprene float straps actually float. Silicone grips stop slipping without a tether. Adjustable cords hold through motion but will bend the arms if you crank them.

Fit the loop to the temple tip, test anything that claims to float, and remember that a retainer is insurance against loss — not a substitute for a frame that fits.