You have to beat Misty. Then, the policeman outside the robbed house will move and you can go in. There will be a hole in the wall. Go through it and battle the Team Rocket grunt. Then you will be able to go to Vermilion City, by jumping down the ledges and going through the Underground Tunnel, or to Lavender Town, by goiong through the Rock tunnel.
Chat with our AI personalities
To get to Cerulean City to Vermillion City, beat the five Trainers at the bridge, talk to Bill for a ticket, then go through the house that has a police guard in front of it. Head south, through the Underground Pass, ahead of some Trainers, then you will enter Vermillion City! To get to Cerulean City fromVermillion, make your way back through Route 6. If you have given the guards to Saffron City some Tea, you can go straight through Saffron and on to Cerulean. If you have not, just take the Underground Path you find near the entry to Saffron City. This will take you right up to Route 5 and just North of that is Cerulean City. If you have the move Cut, you can access the city through the small shrub near the South of it, but otherwise, you'll have to go around and jump off the ledge near the Cerulean Gym.
you cantYou can't get to Mt. Moon from Cerulean City in HG/SS, you have to go through Diglett's Cave and head east from Pewter City.
By walking there from Saffron City or through Rock Tunnel from Cerulean City.
In the Cerulean Gym
you go to vermellion city and then go through the dugglet cave and you will reapear on route 2.