Best river cruise in London. And London eye. Crown Jewels.

You are traveling to one of the most popular European cities during the height of Summer.

City will be crowded and if weather holds temps will be in the 70’s.

Personally I’d reserve in advance. Queues may be lengthy.

https://www.thamesclippers.com/plan-your-journey/timetable

https://www.hrp.org.uk/tower-of-london/visit/tickets-and-prices/#gs.b2vs2e

https://www.londoneye.com/tickets-and-prices/

Crown Jewels. Same questions. Could I buy tickets same day? How long should I plan for it including lines?
Official website?

The Crown Jewels are at the Tower of London - Claudia has given you the official link above. The usual advice is to get a ticket for the Tower for first thing in the morning and head for the Crown Jewels immediately you’re through the gates. Then enjoy the rest of the Tower at your leisure. Later in the day there are considerable queues for the jewels once you’re into the Tower complex. In the summer I recommend buying your tix in advance.

You buy tickets for the Tower of London - not specifically for the Crown Jewels. I mention this for clarity as you’ve only asked about the jewels.

Consider using the river bus sponsored by Uber instead of a cruise. You don’t get the cheesey (and usually nonsense) commentary but it’s a fraction of the price. You can use contactless as for the tube and bus.

It may be relatively simple commentary but is factual.
If you haven't been to London before or on the Thames any of the cruises are a good introduction to the river and it's history.
Yes you can buy on the day for any of the river cruises.
Just turn up at one of the piers.
While I love the Clippers they are just transport, no commentary or information to be had.

You could do all of that in one day

First, go to the Tower of London. Go directly to the Crown Jewels. Then, take a Beefeater tour of the Tower. (It's included in your ticket.) Allow yourself extra time to visit the Tower.

From there, you can get a river boat from the Tower of London to the London Eye.

Get off at the London Eye and take a trip on it.

Give yourself 3-4 hours at the Tower. There is a lot to see.

To my mind a fun trip is to get a river cruise with commentary (not the Uber river bus) from Westminster Pier to Greenwich (by the Cutty Sark, an 19th century sailing ship). If you like, visit the National Maritime Museum - very close and free - and visit the Prime Meridian so your teens can stand with a foot in each hemisphere (everyone does it; I did it on a school trip nearly 60 years ago!)., Then get the Uber river bus one stop downstream to the O2 and walk from there (about 5 mins) to the cable car ride across the Thames. Once on the north side, walk about 5 mins again to the Docklands Light Railway (I think the station is called 'Royal Victoria') and get the small train back to the City.

I was just in London showing first-time visitors around (wedding party).

For the Tower of London, book tickets ahead. We had tickets for 11:30 and arrived around 11:10 and they let us in. We did wait for the Beefeaters tour to start but stopped after the introduction (a lot of people were standing around). We ended up walking around on our own which worked best for us. For the crown Jewels, just get in line (no extra ticket needed). The line looked long when we were there, but it only took about 15 minutes for us to walk in the door.

For the London Eye, go online to buy your ticket. you do not need the fast-track service. Again, the line looks long but it goes down pretty quickly. From the London Eye, You can make reservations, online for the day off, but for the time you will be in London, I would plan ahead there may not be any available slots.

You can use the UBER boats to get to the Tower. Just tap or scan with your phone to get on and off (Just like the tubes). You do not need to prebook the Uber boat.

One thing to bear in mind is the the summer school holidays in England don't start until around the 3rd week in July. So, if you can, try to schedule visits to the most popular places on a weekday so at least you won't be competing for access with British families (although there may well be parties of schoolchildren).

A week isn't very long in London, but if you have the chance I would spend a day at Hampton Court Palace (Henry VIII's palace) which is opposite a train station and can easily be got to independently. Advice is, as always, get there as it opens and do the popular things first. If you can go on a nice day (in London you need to keep an eye on the weather forecast), the gardens and lawns to the Thames are lovely - and the Maze is a must-visit. Expect to spend all day there.

Last summer I thoroughly enjoyed my Thames River Sightseeing Cruise from Westminster Pier to the Tower Bridge (recommended by RS). I booked in advance, but you can also walk up and purchase a ticket. Their roomy vessels have open-air upper decks and enclosed lower decks and include a commentary (which I very much appreciated). They are of course not as frequent as the Uber Clippers and routes are limited, but for my sightseeing purpose, it was the perfect choice. Our vessel passed others on the Thames that were packed to the gills, and I was so happy not to be one of those.

Thanks everyone.

We will be staying next to the south Kensington tube station.

We have decided we are only going to do walking around the city but not go inside places.
Th only plans we are going to book are 1 river cruise, high tea and Kensington palace and Sherlock museum at baker st. We have phantom of the opera reserved on the 1st night.
Otherwise, We want to just walk around and see the sights and th neighborhoods.

I need help grouping activities in 4 chunks.
1st day Am
1st day Pm
2nd day Am
2nd day Pm
Besides what I listed above: tea at Kensington palace, Sherlock museum baker street and river cruise we want to see:
Tower of London outside only
Covent garden
Borough market inside
Bucking ham palace, outside only
Camden market inside
Harrods inside
Sky garden inside

Please if you have time help me with a itinerary by neighborhood and add anything else we could do or where to eat.
We want Indian, fish and chips and yummy but not super fancy or expensive food.

South Kensington Station is very close to 3 bid, free museums; Natural History (includes dinosaurs), The Science Museum and the Victoria and Albert Museum. All are worth a visit and since they are free you can just go in for a short time. They do sometimes have queues to manage overcrowding and/or require a timed entry ticket (even though it’s free) and for a security bag check.

In the science museum, your teens may enjoy the interactive “Wonderlab” but this is charged for and does get booked up.

It may be relatively simple commentary but is factual.

I am an historian and I have been on a couple of the cruises and I can confirm the commentary was largely inaccurate.

Are the teens Harry Potter film fans? If yes you can visit the entrance to the Leaky Cauldron by visiting Leadenhall Market.

Now that you’ve chosen to only see the exterior of the Tower of London you can stroll from there to Leadenhall Market. Simply walk towards the Sky Garden building. Leadenhall is a 5 minute from there.

Rather fascinating architectural dichotomy between the Lloyds of London building and Leadenhall.

Kill two birds with one stone. As a prior poster mentioned, take a trip to Greenwich. Great place to visit as there is a lot to see and do there. You could take one type boat there, and another on the return trip.

Too bad you decided to skip the Tower. Mostly what you see from the outside is a very tall wall and the top of the White Tower... You won't even see where the Crown Jewels are.

But it is your trip to do as you wish.

If you have a map of London, you can use sticky notes to lay out where the sights are you want to visit and see how they group together. Or on a smartphone or computer try Wanderlog. It will arrange your entries for you to reduce doubling-back. I found it very helpful planning my days in Rome. Just noticed you're leaving tomorrow! Have a great trip!