Taking a dip in a pool at sea is one of the most enjoyable things you can do on a cruise ship. Not only is it an excellent way to cool off as you cruise the Caribbean islands or visit Asia's modern cities and majestic temples, relaxing in a swimming pool or whirlpool is a perfect way to take in the views of the destination of your arrival or departure.
These days, cruise ship pools are more luxurious, unusual and more glamorous than what you might imagine - think poolside cabanas, infinity pools and even pools that come with butlers.
See also: Cruise captains reveal the world's best views from a ship
We've rounded up some of the most incredible pools on cruise ships, from Royal Caribbean's surfing pool to the colourful Seahorse Pool by Crystal Cruises.
Want a child-free experience? The beautiful adults-only Solarium on Celebrity Cruises' Solstice Class ships offer a tranquil haven. If you fancy something even more exclusive, the MSC Yacht Club swimming pool is part of a private ship-within-a-ship with a private bar, lounge and access to a poolside butler for a cruise ship experience like no other.
If it's a completely unique pool you're after, Royal Caribbean's AquaTheater has the deepest saltwater pool at sea which provides a theatrical show with synchronised swimming, high diving acrobatics and trampolining - and you won't even need your costume.
Take a tour of the most beautiful cruise ship pools in pictures.
14 swimming pools with spectacular views
In pictures: The world's weirdest swimming pools