Keys are the second-smallest thing you are given at handover and one of only two you must return (the other is the bike). Losing one is a solvable problem with a known cost.
The first question: is it lost or locked in?
Check the obvious first: under the seat, in the under-seat bay, in yesterday’s trousers, the bag you re-packed. Motorbike keys hide in exactly the places you swear you checked. If it is genuinely gone, move to the next section - but the five-minute search is cheaper than everything after it.
What to do
Call the shop and say so, immediately - +84 942 467 674, WhatsApp or Zalo, 09:00-21:00. Two reasons: the shop may hold a spare keyed to the bike (many rental shops do, precisely for this), and the earlier the call, the more options. Losing the key at 21:30 outside the shop’s closed shutter is the bad version of this story; the 14:00 version is an errand.
What it costs
A replacement key for the common rental classes is a small cash item - a basic metal key is cut quickly and cheaply; a key with a chip (on some scooter models) costs more and takes longer, sometimes a day. The cost settles against the deposit at return, along with any call-out or delivery the loss caused. It is an agreed-charge item, not a penalty - expect the receipt, not a lecture.
The prevention, learned by everyone once
- Two-pocket rule: key goes in the same pocket, always, and never a jacket pocket that comes off.
- Never leave the key in the ignition while you dismount “for a second” - unattended keys are how bikes leave without their riders.
- If your rental came with a spare, do not store it in the bike’s own under-seat bay; a stolen bike with both keys inside is a double loss.
- On tours: the spare travels in a pannier, not in the same bag as the main.
Lose it, call it, pay the small bill, keep the spare separate. That is the whole story.