What to wear in an Icelandic ice cave — and what gets people turned away

A crampon is a steel frame with spikes that straps onto a boot. The straps need a solid sole to tension against and a raised heel and toe to hook onto. A trainer has neither. On a soft sole the crampon rolls sideways the first time you put weight on an edge, which on glacier ice is exactly how people get hurt.

So guides check footwear at the meeting point, and they turn people away. This is not officiousness; it is the same check a climbing guide would do anywhere. What they are looking for is a stiff-ish sole, a heel, and an upper that comes above the ankle so that the boot does not fill with the wet sand you are about to walk through.

If you did not bring boots, rent them in Reykjavík before you drive east. There are outdoor shops in the capital that hire them by the day for very little. Finding a pair on the south-east coast at eight in the morning in January is not a plan.

Some operators do include boot hire, and a few advertise it. Read the inclusions on the specific listing rather than assuming, because it varies between tours run by the same company.

Dressing for the cold rather than the wet. Inside a cave it is around freezing — often warmer than the wind outside — but everything is damp. Meltwater drips, the floor is wet sand, the walls are wet ice. A thick dry coat is far less useful than a thinner waterproof one.

Bringing a camera bag with no strap. You need both hands on the walk in over moraine, and you will want them again inside. Anything you have to hold is a problem. A small bag worn across the body, or a jacket pocket you can reach with gloves on, is the whole answer.

Wearing a thick hat. It does not fit under the helmet, and a helmet is not optional. People end up carrying the hat, which means one hand occupied for three hours. A thin beanie or a buff solves it.