Are there any hotels in Prague that have 3 twin beds or 1 king and 1 twin?
Yes, I am sure there are. Have you tried using booking.com or hotels.com and selecting 3 travelers? You will get a list.
Look at the House of the Big Boot in Prague. Google House of the Big Boot Prague and the web site comes up. They have a suite. I stayed there for a week on a Rick Steves tour and loved it. More like a bed & breakfast or inn than a hotel. It is the owner's house, even though they call it a hotel. The owners and staff were very, very nice. I would stay there again. The hotel should be in RS book. Make sure you get the Rick Steves book for Prague. Has great information. I loved Prague and am sure you will enjoy your trip. Have a great time!
Just to add, I stayed there when Rick Steves had the week long Prague tour. You can walk every where and take the tram too.
In my opinion, one should never use one of those booking websites except as a last resort. They tend to feature far less properties than do the town websites and then mostly the more expensive places.
That said, I (reluctantly) used one of Rick's recommendation, and I was pleasantly surprised. I stayed at Guest House Lida. I recommend it enthusiastically. The rates are very good for Prague and the operators, two brothers, are so helpful. They love their town and try to help you enjoy it too. They have triple rooms.
Thanks everyone! I received a private message about The Boot in addition to the thread, so we're looking at it and the guesthouse Lida. Did you find the distance from the city center to be a problem with Lida?
We (family of 4) used Lida Janska (RS approved) to rent an apartment very close to Old Town. Reasonable and very clean. It was on the 3rd floor with no elevator.
I wanted to add a warning about using the booking sites when going to Europe. I have run into a LOT of people who made reservations and paid through a booking site, got a confirmation, then showed up at the hotel only to be told that there was not room for them and that those who had booked directly through the hotel got priority. Apparently there must be a matter of overbooking in many of these places with priority going to those paying full price. The hotel will then book you somewhere else where you might not want to be at a distance from where you planned to stay and it might cost more.
One of the best places in Prague is Residence Agnes. You can get a family room with a king sized bed and a sleeper sofa so 3 can stay in the room. You can see the rooms at www.residenceagnes.cz/family-room It is a very classy and comfortable place.
Hotel Maximillian. Terrific location, excellent service, great breakfast. Spacious room for European standards. Here with my husband and adult daughter. Two twins plus a twin rollout. Daughter says the rollout is comfortable.