Instant extinguish	Notes
Pickups	Picking up a health pack, thrown lunchbox item, or a dropped ammo pack from a dead Heavy that was holding a lunchbox item before death.
Resupply locker	Touching a Resupply locker, switching class in the spawn room, or switching Loadout while in the spawn room.
Water	Entering water below eye level. Puddles and low-level water (such as in the sewer tunnels in 2Fort) do not extinguish a burning player.
Healing	Being healed by a Medic, Dispenser, or Payload cart for a full second.
ÜberCharge	Being the recipient of a stock ÜberCharge. Being ÜberCharged by a Kritzkrieg, Quick-Fix, or Vaccinator does not affect the rate at which fire is extinguished by healing.
Container-based liquids	Being splashed with Mad Milk, Mutated Milk, Gas Passer, Jarate, or Self-Aware Beauty Mark from a teammate or after being airblasted. These items can also extinguish the wielder themselves by throwing their respective containers at their feet.
Airblast	Being airblasted by a friendly Pyro.
Thermal Thruster	Being near a friendly Pyro when they land with the Thermal Thruster.
Dead Ringer	Activating the Dead Ringer as a Spy.
Spy-cicle	Having the Spy-cicle as your active weapon while burning.
Manmelter	Being extinguished by the alternate fire of a friendly Pyro's Manmelter.
Conniver's Kunai	Backstabbing someone with the Conniver's Kunai.
Charging	Charging with any Demoman shield. Only the start of the charge will extinguish the Demoman, if set on fire during the charge it will not extinguish.
Sydney Sleeper	Being hit by a friendly Sniper's Sydney Sleeper.
Darwin's Danger Shield	Wearing the Darwin's Danger Shield prevents afterburn entirely as well as reducing direct flame damage.

Mitigating fire damage	Notes
Healing	Being healed by a Medi Gun, Dispenser, or Payload cart for less than a second. Any kind of passive or on-hit/kill healing such as the Blutsauger or the Concheror.
Bonk! Atomic Punch	Drinking the Bonk! Atomic Punch stops any afterburn damage, but does not extinguish the fire. Additionally, the damage taken from the fire will cause a slowdown effect after the Bonk! effect wears off.
Health	Equipping weapons that increase the player's maximum health, such as the Bootlegger or Batallion's Backup.
Damage resistance	Being under the effects of a damage resistance, such as cloaking or the Sun-on-a-Stick.