How to swim while carrying fins (i.e., when the fins aren't positioned on my feet)?

When swimming long distances, I sometimes want to remove my fins for a few minutes to rest my ankles to prevent tendon injuries, while continuing to swim. However, in some places, e.g. an ocean, I have nowhere to put the fins. How to swim while carrying fins (i.e., when the fins aren't positioned on my feet)?

My equipment:

A lot of open water swimmers pull a tow float. These brightly-coloured buoys are mainly for visibility but many have a small compartment to carry keys, snacks, water bottles etc. making them very useful if swimming long distances.

They're attached to the swimmer with a leash (quick-release in case there's a snag hazard). This leash would give you somewhere to clip the fins; some models also have a cord round the edge for easy grabbing.

I've improvised a tow float from a bright orange drybag and other kayaking kit, but the proper ones are much better.

A lightweight carabiner would clip to many fins. Others might need modifying. A hole could be punched with a leather punch and a loop of paracord tied through it, just big enough to take the carabiner. A larger hole could take a carabiner directly. Hole placement depends on the design of the fins and whether or not you wear neoprene socks underneath (as they would protect from the cord chafing as you swim) but I'd aim for something near the heel.

With a scuba mask + snorkel, just stop swimming

A dead man's float (face down in water, body relaxed) requires no movement from the legs/feet to maintain, as long as you don't need to lift your head to breathe (something a snorkel is very good at).

And if you are in a place with a lot of interesting aquatic fauna, stopping to watch them live their lives as you float motionless is 50% of the reason to go snorkeling. (the other 50% is to get to a good diving spot, as tank time to go from a to b feels wasteful).

I wouldn't even take my fins off as you can give your tendons time too cool off without removing them.

Dragging fins behind you whilst you swim is going to waste loads of energy unnecessarily. They're basically going to act like sea anchors.

If you take time to float and get your energy back, with the fins just in your hands, you can then put the fins back on and carry on when your legs are feeling better.

A small inflatable float might help. You can easily stash it deflated in your waistband, blow it up when you need a rest, and deflate it when you're done.

It's often a good idea to have a mesh bag with you anyway, in case you find something interesting to bring back. That'll be useful for stashing anything else like that.

I think there are a couple of options - one would be to clip them to a belt somehow, this would depend on the design of the fins themselves. Many fins have an adjustable strap on the back of the heel to accommodate different foot sizes. These would be ideal for clipping to, but not all designs include this feature. The fins would dangle and probably get in the way of your legs, depending on how long the fins are. You could also slip them into a light bag to contain them somewhat and then clip the bag to a belt.

A second option would be a light drawstring mesh bag with loops to go over your shoulders, like a backpack - something along the lines of a Duffel Bag. Slip the fins into this and wear as a backpack.