You’ll get HM02 Fly in a house on Route 16. The HM is given to you for free by an NPC inside the house.
Route 16 is just west of Celadon City, so you can access this route as soon as you reach Celadon City in your playthrough.
But you’ll need to use HM01 Cut to cut down a tree blocking your path to the area that leads to the HM02 house.
This is what you need to do before you can get HM02:
- Obtain HM01 Cut from the ship captain on the S.S. Anne in Vermillion City
- Obtain the Cascadebadge by defeating Misty in Cerulean City
- Have a Pokémon in your party that knows Cut
Getting HM02 Fly
Starting from the southwest edge of Celadon City, just above the doorless building next to Celadon Gym, head northwest towards Route 16.
Near the start of the route you’ll find a cuttable tree above you that’s blocking your path.
Cut the tree down.
Travel up and along the path and head into the building on the top left.
Once inside, exit the building going towards the left.
After exiting the building, keep heading west and then enter the lone house in this area.
Talk to the girl in the house.
In return for not telling anybody about her secret retreat, she gives you HM02.
Note: To use Fly outside of battle, you need to obtain the Thunderbadge by defeating Lt. Surge in Vermillion City.
Fly Move Details
|Fly Move Details|
|PP||15 (max. 24)|
|Effect||On the 1st turn, User flies up in the air; becoming invulnerable to attacks. (Except for Swift and Bide.)
Then on the 2nd turn, the user attacks.
At 70 power, Fly is the 3rd most powerful Flying type attack in Gen 1. It can make defeating Grass, Fighting, and Bug type Pokémon much easier.
Since the 1st stage of the attack makes you invulnerable to nearly all other moves, Fly can also work well as an evasive move.
It’s an especially good counter against moves that take a turn to charge such as SolarBeam, Razor Wind, and Sky Attack.
However, be aware that two-turn attacks like Fly give your opponent an opportunity to counter.
While you’re in the air, they could switch to a flying resistant Pokémon like a rock or steel type.
Fly is a good move option for Pidgeotto, Pidgeot, and Aerodactyl, since the most powerful flying type attack they learn naturally is Wing Attack with a measly 35 power.
But Fly might be most useful when taught to your Charizard.
Even though Charizard is a flying type in Pokémon Yellow, Fly is the only flying type attack it can learn. So the move gives Charizard some additional type coverage.
Being an HM also means that Fly can be taught an unlimited amount of times to multiple different Pokémon.
Note: Once an HM move is taught to a Pokémon, it can’t be forgotten. Make sure you choose wisely when teaching HMs to your Pokémon.
How To Fast Travel with Fly
Outside of battle, Fly allows you to instantly travel to any town or city you’ve visited.
This makes it one of the most convenient and useful ways to get around Kanto in Gen I.
Though getting HM02 isn’t necessary to complete the game, it’s highly recommended you get Fly to make traveling between locations incredibly easy.
Note: You can only fly to a town/city after you’ve visited the Pokémon Center in that town/city. The one exception to this rule is Pallet Town.