Grand theft San Andreas how can you go to different islands?

Answer 1

In GTA: San Andreas, CJ has to progress through various missions in the game to enable him to get from one area to another. As he passes a particular mission, an area will become unlocked:

For example: at the end of The Green Sabre mission, CJ will progress to the Badlands. At the end of the mission Are You Going to San Fierro? CJ will be able to enter San Fierro, and then on to the desert areas with his missions for Mike Toreno. After completion of the Flying School missions in the desert, CJ can finally progress to the last area to be unlocked: Las Venturas.

If he tries to enter an area which has not been unlocked, he will automatically become wanted and eventually be killed by the cops.