The north side ofthe island is considered the rough side. Diving can easily be cancelled due to rough seas. Sandals and other all-inclusive resorts will only go out during good weather and smooth seas since diving is not a primary attraction but is a side activity.
I dive the Negril area where there are 2 Couples, 1 Sandals, 2 Beaches, 2 Riu, and 2 Superclubs resorts, and others, that have diving available.
Around Negril is some of the best and easiest diving in Jamaica. Very clear waters, smoother seas (on average), and many dive sites mapped by the resorts. Diving is normally 40, 60, or 90 foot based on your cert card and proficiency. Fish life is not large and is thin. Reefs are good, lots of colorful soft corals, swim-throughs, turtles, rays, and plenty of small macro life. There has been a pod of dolphins living there for over a year that great divers occassionally.