Any recs for hotel in London that are pretty centrally located to lotsa touristy stuff but also offer a family of 4 including 2 growing kids enough space to sleep comfortably? Budget it around $350/night but I can maybe swing a bit more.

When my wife and I were there for 10 days we stayed at the Aloft London Excel.
Not in Central London, but with the Elizabeth line getting to Central London was about a 15-20 min ride.

Well worth the cost savings.

We stayed at the Resident Victoria across the street from Buckingham Palace. Its a 5 min walk to Victoria Station where you can hit the Tube. It was clean, safe, and convenient which is all I wanted.

You may have to up your budget (depending on dates), but the St. Ermin's Hotel in London was absolutely perfect for my family of four. It's tucked away on a side street adjacent to Westminster Abbey. We were able to walk to the London Eye, Big Bend, Churchill War Rooms, St. James Park, Buckingham Palace, Trafalgar Square, and the West End theatres. We used a taxi service and river boat to/from the Tower of London, the British Museum, and Hamley's.

The staff was amazing with our kids (aged 10 and 8 at the time). The hotel has a secret agent/spy history and plays into this theme with the kids. Upon check-in, the kids were given a mystery game to play throughout the hotel, and when they cracked the code were given drink coupons for the bar. The bartender gave them a selection of completely over-the-top cocktails and then made a show out of the preparation. Great fun! The hotel also has a good restaurant, top ranked afternoon tea experience, and had complimentary wine on weekday afternoons.

It was a great experience for my family. I highly recommend.

Marriott used to have the Nights + Flights (RIP) and we stayed 7 days in the London Marriott Hotel Grosvenor Square. It's epic: on the doorstep of Kensington, Buckingham and Paddington, etc.

My go to hotel in London was always the Park International on Cromwell Rd. near the Gloucester Rd. tube stop. There are a number of other hotels ranging from very expensive to very budget in that area.

I like that neighborhood because it is a little quieter but you can get everywhere from there with the District, Circle, and Piccadilly Lines running through. It's also convenient for morning walks in Hyde Park, the Victoria and Albert Museum, Natural History Museum, etc. and there is a giant Saintsbury across the street for snacks, toiletries, or anything else you might need.

I always struggle to find something affordable for my clients when they have 4 people. And its rare its 2 queens. Usually its a double bed and two twins, etc. And of course they jump in price.

I'd strongly consider an AirBnB. You'll get more space for similar cost.

We had good luck at the Kimpton Fitzroy with 2 doubles in 2019


https://www.kimptonfitzroylondon.com/

+1 on St Ermin's. It's also a Marriott property if using points. Easy walk to a couple pubs, the tube, Westminster and Buckingham. Great breakfast spread and some nights they had happy hour. Smallish rooms and super small elevator but 4 of us were fine.

https://clubquartershotels.com/london/trafalgar-square

My go to is Club Quarter's Trafalgar Square. Both Charing Cross and Embankment stations are less than a 3 minute walk.

London ain't cheap. I'd recommend going AirBnb, not that it would be cheaper per se, but you'd definitely have more space than your typical London hotel room.

We have 3 kids so we fall into the black hole when looking for rooms online and we found an apartment/hotel at 130 Queens Gate. When are you going because I think that is going to greatly affect the price. We went in April of last year and it was 399 a night for 3 bedroom apartments with a kitchen. When looking I think it was like double that for May a week later. There were a number of different hotel / apartment setups in the area. It was in South Kensington. I thought it was a good location near Hyde park and the natural history museum plus close to underground stations.

Last summer we stayed at the premier inn at county hall. It's right next to the London eye and across the bridge from Big Ben, Westminster. Great location. Very affordable given the location - very walkable and safe. Under 200 pounds per night - easily half of what other hotels were charging. They had rooms for 3 and 4.

Similar to a Hampton inn - room was plain and nothing special. No real character - surprising given the building - but given the prices and our 2 rooms X 3 nights it was a great choice for us. Plus the rooms had great AC and were quiet.

I'm just getting back. First time in London and Paris.

I'll never go back to London. Paris was wonderful. Hope I get to do it again.

Obviously not intended for OP since he is already booked, but if anyone is considering both, choose Paris. Or Rome.

No recs on hotels. I stayed near the Thames just south of Buckingham Palace. It was small and expensive. Bathroom was terrible.