“Lockers available” is reassuring until your suitcase will not pass through the opening. Hostel storage varies: a room may have a tall cabinet, an under-bed cage or a small compartment intended mainly for valuables. A listing rarely tells you everything in those two words.
As one concrete example, St Christopher’s luggage guidance describes padlock-secured room storage and separate arrangements before check-in and after check-out. Its information also notes variation between hostels. Treat that as an illustration of what to ask, not a promise about another property.
Ask about the opening as well as the space
Send the hostel your bag’s approximate external dimensions, including wheels and a rigid frame. Ask whether those dimensions fit through the locker door. A cabinet’s internal volume can sound generous while its opening is too narrow for a hard-sided case.
Find out whether the lock is built in, supplied separately or brought by the guest. If you need your own padlock, ask what size the fitting accepts. A large lock is not useful if its shackle will not pass through the hasp.
Separate the overnight plan from departure day
Your room locker may stop being available when you check out. Confirm where a bag can go before a late train, how that space is accessed and whether a fee or collection deadline applies. Put the collection time beside the transport departure in your itinerary.
At arrival, check the door and closure before leaving belongings. Report damage or a mechanism you cannot secure to reception. Keep essential documents and items you need during the day accessible without spreading your entire bag across a shared room.
A short message before booking can settle most of this: bag size, locker opening, required lock and departure-day storage. It is more useful than packing several speculative padlocks and hoping one solves the problem.