The cheapest Oslo to Chiang Mai return flight on the radar right now is €823, flying with Thai Airways via one or more connections. It covers departures in December 2026, and every dated link below opens that exact OSL–CNX search on Skyscanner. The price we usually record on this route is €722. Across 47 recorded checks it has ranged between €506 and €868. Our sampling points to December 2026 as the cheapest month to fly Oslo to Chiang Mai.
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 Oslo? We track 54 other departure cities for Chiang Mai, 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 Oslo to Chiang Mai is often still worth booking within a day or two of the fare we found.