What's included at one all-inclusive resort may different from what's included at another. The vast majority cover the basics, but be sure to check out the specific resort you're considering to find out what is included.
Nonalcoholic drinks (soft drinks, juices) are included at all-inclusives. Alcoholic beverages are included as well, but brands may be limited, with premium ones unavailable or available for a price.
Meals are always included at all-inclusives, although choices vary. Some all-inclusive resorts will include only buffet restaurants or might charge for more expensive dishes in their restaurants.
Included activities will vary depending on the all-inclusive resort; however, they are almost always limited to nonmotorized water sports and do not include things like water skiing or jet skis.
Transportation to and from the airport is usually included at an all-inclusive resort. Transportation out of the resort (into town or outside activities) is usually not.
Tipping policies vary greatly from resort to resort, but in general tips are included at all-inclusives.
The major all-inclusive resort brands such as Sandals (which includes Beaches, Royal Plantation and Grand Pineapple) and Super Clubs (Grand Lido, Breezes, Hedonism and Starfish) usually offer more amenities than small chains or single hotels.