What age is an adults only resort? Typically, you'll find the minimum age requirement for guests at an adults-only resort to be 18 and over. Some resorts do consider guests between to be adults, so it's best to check with each resort. Remember to bring your passport or ID with proof of age/5. #7 Best Value of 24 Adults Only and Adult Friendly Resorts United States “ Very friendly staff, clean rooms, non-smoking, perfect view of the ocean, adults only, dolphins, daily walks to John's Pass on the beach, and quiet evenings on balcony listening to the waves is spectacular.