10 Days for London, Paris, Amsterdam - Itinerary Help!

However you portion your time, bear in mind travelling between locations is a minimum of half a day.... by the time you check out, travel to the train station (Eurostar you have to check in about an hour before it leaves I think) and then travel to your new hotel. It would be my gut feel to pick 2 locations and divide your time between them.

Try to figure out what you want to do in each city. What interests you? Go through your guidebooks and see what's more important to you.

I would guess there's more to see in Paris, however, than in Amsterdam.

You could also tweak your time in Paris and Amsterdam a little based on which train you book - early or late - between cities. If you have four nights in Paris, maybe you could take an early train to Amsterdam so you get as much of that first day there as possible. Or if you do three and three, you could take a later train to Amsterdam (leave your bags at the hotel or the train station for the day after you check out) and have three nights but really two full days.

All 3 for the time you have, makes "choosing two" the better option.

If you decide to do all 3, my choice would be Paris and & London 4 each and 2 for Amsterdam

I definitely recommend 4-4-2. Paris has way more to do than Amsterdam. If you aren’t intersted in museums in Amsterdam, you could even do 4-5-1, assuming you could get to Amsterdam by noon.

Your first full day there may still have jet lag issues, so I would apportion longer to this than Paris, although there is enough in either city to fill your 9.5 days! With trying to squeeze in Amsterdam as well, there is no right way to apportion your time, as allowing for travel time between places, you will be short changing all three IMO.

Decide as a family what you want to see in each place and book accordingly, as posters here will have different priorities to yours.

Thank you all for such immediate responses! Here’s a follow up question: Will European hotels in general allow us to keep our luggage at the hotel even after we check out? For example, if we check out of a hotel in Paris on 8/23 at 11 am, will they let us keep our luggage there until the evening, so that we can catch a night train to Amsterdam? As some of you have said, I’d hate to “waste” half a day traveling. I’d rather sightsee during the good part of the day and use the night time to travel...

I’d rather sightsee during the good part of the day and use the night
time to travel..

Most hotels will hold your luggage for a few hours. But I hope you don't literally mean taking night trains to Paris or A'dam. Do you mean evening trains? Because a night train will mean little to no sleep on the train, and fatigue the next day. And not all hotels have a front desk manned 24/7.

I would have gone 3-4-3 but starting with 4 nights in London, I would choose train timings like this ...

August
14. Arrive late morning in London
18. Early morning Eurostar to Paris
21. Evening Thalys to Amsterdam
24. Early morning departure from Amsterdam

Choose a hotel with easy access to Gare du Nord in Paris, maybe something right by St Michel stop on RER Blue Line. Likewise something close to Central Station in Amsterdam.