You need the Fog Badge from Morty the Ecruteak Gym Leader in Ecruteak City before you can use Surf outside of battle.
In one of the gyms. I don't know witch one.
it's the badge from crasher wake
the badge you need is the 4th one and also if you have not already you can get surf in the dance theater.
Hearthome's badge
You need 4 badges.
Cynthia gives you HM03, Surf, in Celestic Town. The Relic Badge is needed to use it in the field.
You need the Fog Badge from Morty the Ecruteak Gym Leader in Ecruteak City before you can use Surf outside of battle.
In one of the gyms. I don't know witch one.
get the HM surf and the corresponding badge.
it's the badge from crasher wake
the badge is strombadge
the badge you need is the 4th one and also if you have not already you can get surf in the dance theater.
6th gym badge
Hearthome's badge
Soul Badge (Fuchsia Gym)
You get it in canalave city after you get surf.