You can use the usual hotel booking sites which provide a large number of hotels within London. You might want to chose a hotel that is easy to reach by public transport (bus or tube).
There are also several reasonably priced hotels north of Imperial (on the other side of Hyde Park, around Lancaster Gate/Paddington), which are within walking distance.
Right next to Imperial College is Princes Gardens, which is student accommodation:
https://www.imperial.ac.uk/visit/summer-accommodation/
It can be booked through this website - but also on booking.com.
Below, we also have a selection of preferred hotels with a negotiated rate for Imperial guests along with instructions on how to access the negotiated rates. These hotels we would usually recommend for guests coming to campus but they are still somewhat more expensive than the options above.
Gem Hotel (Strathmore)
Single - £168
Standard Double/Twin - £186
Executive - £222
Guests may make their own reservations at the negotiated rate via our hotel website by entering the code 13-0BQ9 at the time of booking.
Fraser Suites
Studio Premier - £162
Studio Deluxe - £180
Studio Executive - £192
Guests can book individually online, via a link provided by our reservation department
The Rembrandt Hotel
Classic Double - £209
Executive Double - £239
Executive King / Twin - £ 259
Use code IMPERIAL when booking on the website.
The Gore Hotel
Classic Double Room - £ 215
Superior Double Room - £ 240
Deluxe Double Room - £270
Guests must acquire an Imperial signed email before booking directly via email or phone to access negotiated rate.
We advise booking your hotels as soon as possible, as vacancies can become limited in this season.