First,
You go to route 104.
Then,
There will be some water.
You have to have a water type to do this.
You have to use HM surf.
Then you have to just avoid the big boulders
until you reach shore.
After you defeat Brawly the Dewford Gym Leader and give the message to Steven Stone, go talk to Mr. Briney near the port and he'll ask you if you want to go to Petalburg or to Slateport City, choose Slateport and he'll take you there. Follow the path North (you can take the grass route or the Cycling Road route) and you'll make it to Mauville City, the home of the 3rd Gym.
You have to explore the cave off that city where the Trainers' School is located. (Sorry, I forgot its name and I'm going off memory here.) I think so. If not, explore EVERY cave you see and inside will be Mr. Britney, who will take you to Dewford if you rescue him. Go figure.
;)
---PokeFreak
you need to rescue mr brainey and get him to take you on his boat
on route 104 (right ouside of petalburg city) there is an old man named Mr.Briney if you have saved his wingull named peeko he will let you ride on his ship to either slateport or dewford
before petleburg wood there is a cotage you will find him inside there
at dewford town.
There is no dewford town in pearl. Only in Ruby Sapphire and emerald. correct me If I am wrong
close by dewford town
Dewford town.
There is no Dewbridge city. There is Dewford town, though.
you can find regiice near the dewford town,surf northwest.
Use mr briney's ship to reach dewford town.
in dewford town
He is in Granite cave on dewford town you give him the letter in the cave.
Brawly is a fighting type and he is located in Dewford Town and he has a machop and makuhita
go to dewford town and go into the cave and talk to the hiker he will give you hm05
Go to dewford town and talk to the fisherman outside he will give you the old rod.