I call them "banana lounges" although if you Google images of banana lounges, they might be slightly different. By the way, you should say "WHAT do you call the beds at the beach?"

Sun lounger. Sun bed is something you tan on indoors.

I agree with Paul. I'd call them 'sun loungers'. The word 'sunbed' suggests the beds in an artificial tanning salon. I like the idea of a 'banana lounge', but it does seem to be an exclusively Australian term.

A 'sun lounger' is what I would call it. 'Sunbed' is possible I suppose, with context people would know what you meant but to me, the most common use of 'sunbed' is to describe the beds used in tanning shops which use UV light to give someone a tan. Like this: http://news.images.itv.com/image/file/24906/image_update_9beeaa86f11a6b05_1335936168_9j-4aaqsk.jpeg

I would call them sunbeds.... :)