Bruxelles / Brussels to London by train

Final Destination: London St. Pancras International

Some trains also call at : Ebbsfleet International; Ashford International (These station calls have been suspended until 2023)

Note that London is in a different time zone to mainland Europe, it is one hour behind, so when looking at a timetable the journey will look as though it's an hour shorter.

Eurostar is currently recommending that that Standard Class And Standard Premier ticket holders should be at the Eurostar departure area 60-75 mins before departure; and that Business Premier ticket holders should be there 45-60mins prior to departure.
The departure gates will close 30 mins prior to departure for Standard Class And Standard Premier ticket holders; and 15 mins prior to departure for Business Premier ticket holders.

Book early and save: Yes

Online bookings open: up to 330 days ahead of the travel date.

Also note that on the Eurostar booking site, it only uses the English name of the main station in the Belgian capital - so enter 'Brussels Midi' into its search

The price shown above is the standard, most heavily discounted, one way Standard Class price.

Eurostar frequently offers special fare/deals promotions, so the price you see on the home page of the Eurostar website MAY be cheaper.
But check the terms and conditions of these deals BEFORE making a booking. The special price MAY depend on additional factors, such as the need to book a return trip and/or MAY not be available when making day trips.

The booking path on the Eurostar website is comparatively straightforward and an advantage of booking direct with Eurostar, is that it offers its ticket purchasers the ability to choose specific seats from a seating plan (after the booking has been made).
As the fabulous Seat 61 explains here in detail (scroll down to 'Choosing A Seat') some seats on Eurostar services are better than others.

The different types of ticket summarised

Also worth knowing is that when travelling by Eurostar you can choose between three classes of service, and this also impacts on the exchanges and refunds of what Eurostar refers to as 'Flexible tickets'

If you book Standard or Standard Premier tickets, you can exchange them if need be, to an alternative departure on your booked route; but if you want to transfer your ticket to a new departure less than 7 days before your travel date, you will need to pay an admin fee of £30 for Standard Class tickets, £40 for Standard Premier tickets PLUS the price difference with the new ticket you will be booking.
What's new, in response to the pandemic, is that these £30/40 charges aren't applied if you want to transfer to an alternative departure more than seven days before your travel date.

Business Premier tickets are less restrictive, in response to the pandemic they can now be refunded and they can be exchanged to alternative departures without paying the admin fee, or the price difference.

Eurostar's full ticket terms and conditions are here

Using Rail Passes on Eurostar:

Rail pass users can now pay reservation fees to travel on Eurostar trains, in a similar manner to other international European high speed trains.

The new rail pass reservation fees are similar to the cheapest single journey ticket prices, but as those cheapest tickets can sell out quickly, it's likely that the rail pass reservation fees will save money.

You can purchase these online with no booking fees via B-Europe - or they ARE now available on the Eurostar website.
Booking in advance is recommended as it's not unknown for rail pass reservations on Eurostar services to sell out days or weeks in advance, there is evidently limited availability per departure.

You can obtain a rail pass reservations without paying a booking fee at Eurostar stations.
However, if you want to do this on the day of travel be prepared to be flexible re: the train you will take.

If you are a UK resident, your rail pass + reservation is only valid if you take a train from the UK on the first day that your pass is valid for and return to the UK on the final day that you will be using a pass.