From Bulbapedia, the community-driven Pokémon encyclopedia.
The Seabreak Path (Japanese: 海割れの道 Seabreak Path) is an extension of Route 224 that leads to the Flower Paradise. It is only accessible if the player has the event-only item Oak's Letter, and, as such, can only be legitimately accessed in Pokémon Platinum and Brilliant Diamond and Shining Pearl. Although Oak's Letter was not distributed for copies of Pokémon Diamond and Pearl, glitches such as the surf glitch, tweaking and the void glitch can be exploited to access this area.
Geography
Seabreak Path has no distinctive geographical features of note. It is, however, the longest route in any core series game. With a length of about 256 units and 8 blocks on the Town Map, it would be impossible for a game from Generation III or before to support this path without dividing it into several segments. Once unlocked, it can be popular among players for Egg hatching.
The path is covered in flowers of many colors, and it is surrounded by ocean on both sides. This ocean cannot be Surfed upon or fished from, as the path is raised above sea level. It stretches the entire length of the Battle Zone, from the Resort Area to Stark Mountain.
Shaymin event
The Key Item Oak's Letter will trigger an encounter with Professor Oak at the northernmost point of Route 224. The professor will explain the myth of the white rock: that any Trainer who visits the rock may inscribe upon it what they are most thankful for. There are few limits to what may be written here; the input system is identical to the system used for nicknames.
By giving thanks, the player unlocks the Seabreak Path and has the opportunity to go to the Flower Paradise and catch Shaymin.
Layout
Music
Trivia
Name origin
According to the Town Map, Seabreak Path is so named because it breaks the sea between the Sinnoh region and the open ocean that lies to the east.
In other languages