Lapras Travel Liner (Japanese: ラプラス大陸便Laplace Intercontinental Travel) is the mode of transportation between continents. Lapras will be in Lively Town as soon as the player makes it there, but access to her transportation will not be available until later on in the story.
After living at the Expedition Society Headquarters for a while, Archen will ask the player if they have been to other continents yet. The next day, he will buy two Lapras Liner Passes for the player and partner and take them to the Air Continent. After the day's expedition is done, the player will be able to buy the rest of the Lapras Liner Passes at Kecleon Shop.
After completion of the main story, the player can connect with Lapras by talking to her and she will allow the player to go to "The Remote Parts of the World", also known as the Sea of Wonders. As the player increases in Expedition Rank, or clears certain dungeons, more dungeons in the Sea of Wonders will become accessible.