Hi wheatcrunchie,
We went the first two weeks in May and most places were just opening, including some hotels. The costa caribe water park was open but only the indoor bit, that didn't open till the end off may fully. Port Aventura was open and really queit so no queues.A lot of pubs and bars were just opening too so they wern't really crowded.
We had a great time, the only down side was the weather. The first week was like a wet week in whitby But it picked up during the second week.
Think most things will be open by the end of may.

been in may and june, but would say go the last week in may and the first week in june. we went this year on the 11th june for two weeks and it was the spanish holidays and you couldn't get near most of the rides in portaventura for 1- 2 hours. very hot too.

Thanks
I've booked to go on May 29, so hopefully eveything will be open. Not that I mind if it isn't. Just nice to get away.