How can I kill 4 hours in Biarritz area this afternoon

I will be in Biarritz between 4pm and 8pm this afternoon with nothing specific to do. Any suggestions? I like walking, and also thought I might drive into Spain to find a supermarket and buy some local produce there. Any recommendations?

I am not impressed with Eroski or the shopping centre there, much prefer Alcampo, great coffee bar and better surrounding shops and easier/quicker to get to. Better selection of restaurants to eat in if we do not have time to go into Irun town.

Hello

We do all our shopping in Eroski at St Sebastian - much better than the French owned Alcampo - fantastic fish counters and overall larger ‘grand surface’