From Pallet Town, the route begins as a small channel of water. South of the town, an outcrop of land on the route's east side holds the only grassy area on any water route in Pokémon history up until Generation IV. Past the grassy area, the mainland terminates and the route widens significantly in size.
South of this point, the look of the route varies greatly by generation. In Generation I, there are two small bridges containing two Trainers each spread out along the route. Five other Trainers are also found along the route. In Generation II, the bridges remain but only one Trainer is found on one of the bridges. Two more Trainers are located in the water. Generation III replaced the bridges with sandy islands and added five additional islands as well. Trainers can be found on four of the islands, as well as in five locations in the water, making a total of nine Trainers.
In every generation, the route runs directly north-south in the water, reaching its southern terminus at Cinnabar near the southernmost Trainer.
Between Generations I and III, the route is the same with the exception of a few minor cosmetic changes. In Generation III, the bridges are replaced with sandy islands and five additional islands are added as well. Trainers can be found on four of the islands, as well as in five in the water, making a total of nine Trainers.
The route was shortened considerably in Generation II. The basic design of the route, however, was almost identical to that of Generation I.