Some links on this page may be affiliate links. If you buy through them we may earn a small commission, at no extra cost to you. As an Amazon Associate I earn from qualifying purchases. How this works.
The quick answer
At four, a float suit or vest with removable floats works well: take floats out one at a time as they get braver. A sleeved float suit suits chilly UK beaches, and a flat-packing vest suits holidays. Swim aids are not life jackets, so stay within arm's reach.
Four is that in-between age: too big for armbands, not quite swimming alone. A float suit or vest with removable floats lets you take away support bit by bit as they get braver. On boats, it's a proper life jacket every time.

Splash About Sleeved Floatsuit
Splash About Go Splash Swim Vest
Verity hasn't tried this lot yet. Her honest verdict goes here once she has, good or bad.
Questions parents ask
Float suit or swim vest?
A sleeved float suit adds sun and wind protection for UK beaches. A vest packs flat for holidays. Both let you remove floats bit by bit.
Is a swim aid the same as a life jacket?
No. Stay within arm's reach in the water, and use a proper life jacket or buoyancy aid on boats.
When should I take the floats out?
One at a time, as they get more confident. There's no rush.