Hiya were off to Bahia Tulum in two weeks from my understanding you can only use coba and Tulum resorts
you can use Akumels beach as that doesn't belong to the hotel but non of the all inclusive facilities

Must have changed then ; we went in 2011 and stayed @ GBP Coba; the only restrictions that I can remember were that you couldn't use the special a la cartes in the other "hotels" -you could use pools/ bars/buffets everywhere and the beach was unrestricted. Presumably you can't use the facilities in the Sian Kaan area as that is "Grand Luxe".

Yes it has changed. We went last year and stayed at Akumal and everything was great. Now if you are in tulum or Coba you can only use the facilities for those sister hotels whilst if you go Akumal you get to use everything.

We were unaware of this and wasn't told this when we booked. We phones Thomson who said it would cost another 2-3,000 if we were to change to Akumal. I looked on their website the same day and it cost just 97 pounds extra each... So we screen shot the website and they had to change it to that price. Instead of 14k for our party we get in for just over 12k.

Very stressful. But now sorted we can look forward to it. Good job I checked trip advisor.

This is also confirmed by a reply from the hotel.