Windsor Castle
 

In July we will be staying at the Imperial College in London near the South Kensington Underground. How do we travel to Windsor Castle? How long does it take? Is there a guided tour?

You can take the train from Paddington or Waterloo stations. There is not a guided tour as such. There are people in each state room to answer your questions and there is an audio guide you can hire.

The Paddington train goes to the Windsor Central station but requires a change of trains at Slough. The Waterloo train goes straight through to Windsor Riverside w/o changing trains - but the Riverside station is a bit longer walk from the castle. So it is really 6 of 1/half dozen of the other which train is better . . . . .

Check out the London Walks tour. Took it a few years ago. Met at a subway station and the guide gave us our tickets and escorted us on the train to Windsor. As I recall, I just paid at the meeting.

Terrific guide and we toured Windsor, the Chapel and Eton. As it turned out, a fellow traveler was from my home town and we stayed later and had dinner in Windsor. Our train ticket was good for an "anytime" return.

This was an all day tour and very worth it.

From South Kensington i'd definitely take the Tube to Richmond and from there direct trains to Windsor Riverside station that depart Richmond at least twice hourly and take 35 mins (from Richmond) - this would be the quickest and more seemless route and also much more prettier than the mainline route via Slough from Paddington, requiring a change there as well, to Windsor Central Station.
And both Riverside and Central stations are a very very short stroll from the castle entrance - though Central may be a few steps closer i suppose. Both are located at the foot of Castle Hill.

Yes - both stations are at the foot of Castle Hill -- however, Windsor Riverside is on the "wrong side of the hill", and one has to walk all the way around the castle and up to the entrance. Easily 3 times farther than from Central station.

Not a big problem - but do keep it in mind when choosing which train you choose.

3 times sounds much farther

but the Riverside station when i walked to it from the Castle in Feb was about a 5-min walk

Not really possible unless you go at a dead sprint. Yes - to the foot of the Castle - but Riverside north of castle and the entrance is all the way around on the south side. It takes 5+ minutes from Central - being nearly a 1/4 mile from the entrance. Riverside is a bit over 1/2 a mile from the Castle entrance.

1/4 mile farther - if you walk at 3mph then it's 5 minutes farther, right - not a factor IMO for anyone not physically challenged - but as you said go with what train is most convenient for your London location as both stations are very close to the castle so that should not be a factor.

Both Windsor stations are very close to the castle. Central is a bit nearer the entrance, but it's not significant.
From South Kensington, the simplest route, as PalenQ suggests, is on the District Line to Richmond, then by train to Windsor & Eton Riverside.

Indeed one could make the case that going to Paddington and then walking thru the maze of that large station finding the right platform and getting to it from the Tube station and changing at Slough could actually make going that way longer, step wise than taking the train to Riverside-Eton station

And as IMO any component of a Windsor visit should include a stroll across the humpbacked Thames bridge right by Riverside-Eton station to see the environs of the famous Eton College, then when you wrap up your Windsor-Eton day Riverside-Eton station will be closer when leaving Eton as it's right by the only bridge to Eton.

Again as I said waaay back in my first post -- 6 of 1/ half dozen of the other. It really makes no difference which train/station one uses. If you want to take the tube out to richmond and then catch a train - that works fine. Or taking the tube to Waterloo and taking a train works too. Or taking a cab to Paddington - works.

Which ever you choose - you will have to change somewhere - either on the tube to Waterloo, at Richmond, or at Slough from Paddington. None of them are bad choices.

PQ: The bridge is the extension of High Street (Thames street where it curves around the west end of the castle) so just about as convenient from Central, Riverside, or the Castle exit in the Lower Ward.

Thanks so much for all the good details. It sounds easier to do than I had thought.

Another vote for the train from Waterloo. And IMO, it's not just 6 of one, half dozen of the other. Reasons why:
1. Trains from Waterloo to Windsor have AC. You might or might not need/appreciate it in July. Most of the local trains from Paddington to Reading or Oxford (which stop in Slough) don't--of if they do (in theory), it's broken the day you happen to travel.
2. Trains from Waterloo to Windsor have ticket checkers on board to make sure travelers do have tickets and that anyone sitting in the "quiet" car follows the rules and keeps their voices down and doesn't yap on their mobile phone or have loud, tinny music leaking from it. Unfortunately, most of the trains from Paddington to Slough (your stop) won't have anyone on board to check tickets (although the recently added ticket turnstiles at Paddington do help some) and to clamp down on unruly, rowdy behavior.
3. No stairs (not a big issue, but I don't like that mad rush up and down the steps to track 1 for the Windsor train and the frustration that follows if you miss the connection by one minute).

One other general note: the local trains to Slough from Paddington usually leave from tracks 13 or 14, which are way off in the station boondocks; if you have heavy luggage or shopping bags (which the OP won't, of course), it feels like you have to walk halfway to Slough just to board the train.

I just visited Windsor Castle last weekend.

To take the train, check for schedules at Nationalrail.co.uk

There is free audioguide which is very good. They also offer guided tours (free as well) but I didn't take one.

When I was there, I arrived just before opening time (9:45am). If you arrive later, expect a line to get in.

I spend the first hour around the grounds, listening to the audioguide, plus St Geroge's Chapel.

At 10:45am I found a good spot to watch the 11am changing of the guards, which took about 40 minutes.

I left at the end of the changing of the guards to get in line for the Doll House + State Apts. I waited ~5 minutes in line. The doll house + State Apts took about 1 hour.

When I exited the State Apts, the line for the Doll House is now 45 mins long!

I spent about 3.5-4 hrs at Windsor Castle. When I left, there was a long line outside to get in.

So, basically 3-4 hours but expect longer if it's crowded and if you want to watch changing of the guards (if it's offered that day).