You can usually board the Caledonian Sleeper a while before departure, and guests in the top rooms get earlier access via the station lounges. At London Euston, boarding the train itself typically opens around 45 minutes before departure. Because the Highlander to the Highlands leaves at about 21:15 and the Lowlander to Edinburgh/Glasgow just before midnight, that means you can generally get on board and settle in from around 20:30 for the Highlander and from roughly 22:30–23:00 for the Lowlander. Guests booked in Club En-suite and Caledonian Double rooms can also use the London Euston Guest Lounge well before that, with lounge access opening in the early evening — a comfortable place to wait, with refreshments, before you board. If you're travelling with a bicycle, aim to arrive about 20 minutes before departure so staff can load it. There's no need to arrive hours early as you would for a flight, but giving yourself time to find the platform, locate your coach and unpack for the night makes for a more relaxed start. Boarding times can differ by station, route and timetable period, and can be affected by engineering works, so check the arrangements for your departure. As a rule: plan to be on board around 30–45 minutes before your train leaves, earlier if you have lounge access.
Sources: sleeper.scot
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