Hi David!
Welcome to planDisney.
It's always a pleasure to assist my fellow guests from the UK, and I'm happy to help look at the various ticket options for you. I see that your trip is literally just around the corner, so let's get started -
The following prices are correct at the time of writing, but are always subject to change.
There is currently a special offer of US$ 464.34 (including tax) for a 4-Park Magic Ticket for one admission per day to each theme park over 4 days (there is a 3-Park Magic Ticket, but it doesn't include entry to the Magic Kingdom). If you upgrade to add Water Parks and Sports, the price would be US$528.24 (including tax). With this upgrade you have 4 days of entry to whichever water park is open (Disney's Typhoon Lagoon or Disney's Blizzard Beach).
Typhoon Lagoon is open now.
However, if you only want to visit a water park on one day, you can buy a separate 1-day water park ticket for US$52.19 (including tax).
Unfortunately, you cannot buy these tickets from the UK, but once you arrive in the US you can purchase tickets at any Guest Relations window at all the Walt Disney World theme parks, and water parks, and at the Ticket Center at Disney Springs. You can also buy tickets online in the US at https://disneyworld.disney.go.com/admission/tickets/theme-parks/.
If there's any possibility you'll need theme park tickets for more than 4 days, I urge you to check the prices of our
UK Magic Tickets. They offer great value, and can be purchased in advance of your trip, but for 3 days + 1 day at a water park, I think the US tickets I have detailed above are the best choice for you.
Please come back and visit us if you have any further questions, and you can
send me a direct question if you wish. We will be happy to help you plan your magical holiday to Walt Disney World.
Sue