If you are a "Pokemon Sun and Moon" player and want to catch Gyarados, you have reasons. It is one of the strongest Pokemon in the game and it is natural for players to have Gyarados in their Pokedex. As the game does not yet allow trading, one has to find it to catch it. This is where an SOS battle with Magikarp helps. This method can get a player Gyarados.
However, the Magikarp way takes time and not all encounters produce Gyarados. Not every time Gyarados responds to a Magikarp's call. This is why "Pokemon Sun and Moon" players must know the places where Magikarp nests are located in the Alola region islands. As per reports, Magikarp may be found in Melemele Island in Kala'e Bay, Melemele Sea and Melemele Meadow.
"Pokemon Sun and Moon" players in Akala Island will find Magikarp in Routes 5, 7, 8, and 9 in Paniola Town. Malie Garden, Routes 13, 14, 15 and the Secluded Shore in Ula'ula Island also have Magikarp. In Poni Island, players should look in Ancient Poni Path, Seafolk Village, Poni Gauntlet, Poni Wilds, Poni Plains and Poni Breaker Coast.
Now that the places to find Magikarp have been laid down, it is important to know how to catch Gyarados. Even though coming across Magikarps is not that difficult a thing, players must know that getting a Gyarados respond to its call is definitely a problem. "Pokemon Sun and Moon" players must be ready with a False Swipe move to make Magikarp call for help.
The False Swipe move drains the wild Pokemon's HP down to one and this is when it starts calling for help. In case the Pokemon that responds to Magikarp's call is not a Gyarados, players need to zero its HP to call another one. Repeat this process until a "Pokemon Sun and Moon" Gyarados appears.