[OSS Oxon] Swimming in warm places

Dear swimmers, i am fairly new to this list and enjoy reading what you do here, swim all over places. I moved from NW Canada for work and would like to go around Europe while here in UK. I've seen you also do swimming trips to many EU destinations and i wonder if someone could recommend where to go(warm places). I am not a great swimmer but i can swim a km or two in one Go. I see firms swim trek and strels are offering trips down in croatia, italy, greece. Any advise on this would be greatly appreciated. Hope to join you in the water soon. Thank you, Ben