Mary Gate of Heaven in Negril and Our Lady of Fatima in Ocho Rios. We have been to both and they are absolutely wonderful with locals that are warm and welcoming We celebrated our 50th at Mary Gate of Heaven. There is easy transportation from resorts to each.
I don't know which resort you are going to, But last time we were at CSS I decided I had better go to mass at least once during our vacation since we would be traveling one of the Sundays, so I asked at the desk, and they got a bus to take me to church, and then he waited for me to take me back, no charge. I don't off hand remember the name of the church, but it was beautiful, and they were quite welcoming. They get a lot of people from the resorts in the area. Just ask at the desk and they will help you.
It depends on which resort you're going to. CN provides transportation to both Catholic and Protestant services Sunday morning about 9 AM at no charge. You'll have a blast worshipping in Jamaica. It can be fun to take God on vacation and experience worship with a different culture!!
Our Lady of Fatima is about 15 mins away. I told them I wanted to go to mass, the staff got a shuttle for me. The driver was awesome, he promised me he would be waiting for me after mass and he was. I was rather nervous going by myself but I really enjoyed it.