The cheapest London Gatwick to Hanoi return flight on the radar right now is £347, flying with Air China via one or more connections. It covers departures in February 2027, and every dated link below opens that exact LGW–HAN search on Skyscanner. That is roughly 16% below the £411 this route usually costs. Across 77 recorded checks it has ranged between £326 and £658. Our sampling points to February 2027 as the cheapest month to fly London Gatwick to Hanoi.
Prices are re-checked against Skyscanner automatically, and every one shows when it was last confirmed, so nothing here is older than it looks. Not flying from London Gatwick? We track 60 other departure cities for Hanoi, listed at the foot of this page.
Prices like this tend to vanish fast. If it has gone when you look, try the days either side of the dates above, since London Gatwick to Hanoi is often still worth booking within a day or two of the fare we found.