Pink Rathians are an exceptionally powerful subspecies of Rathian and are available as rideable companions in Monster Hunter Stories 2. You won’t be seeing Pink Rathians until the post-game, so make sure you beat the final boss before you start looking for them.
So long as you’re doing high-rank content, Pink Rathians can actually be found in a number of places.
Single Player Locations
If you want to find a Pink Rathian in single player, you’ll want to head to Pomore Garden in Lamure. Pink Rathian eggs will be available in any high rank den in this area, though there are a number of monsters in the egg pool, so you may have to check multiple dens.
Rare high rank dens will generally offer better genes for your Pink Rathian, so prioritize those if that piques your interest.
High rank dens are easily distinguishable by their bright red color, in contrast to the earthy stone of regular dens. Rare high rank dens share their golden hue with regular rare dens, however, so you’ll have to go to the entrance of each rare den to ensure that it’s actually high rank before entering.
Flowery Dens are the principle co-op location for finding Pink Rathian eggs. With an N Ticket, you’ll only be able to find them in the main monster nest that’s guarded by the boss, though.
An R Ticket will allow you to find Pink Rathians in both the main and smaller nests and their main nest egg pool is pretty small, to boot. Using an SR Ticket will actually remove Pink Rathians from the main nest’s egg pool, but you’ll still be able to find them in the smaller nests.
Early September’s content update added another co-op quest for finding Pink Rathian eggs: Water Eggs. Once again, an N Ticket will only let you find Pink Rathian eggs in the main nest, which is guarded by a powerful Soulseer Mizutsune in this quest.
R Tickets will feature Pink Rathian eggs in both the main and smaller nests, while an SR Ticket will strictly have them in the smaller nests. If you want to try co-op dens but don’t want to go online, keep in mind that you can play locally and simply start the quest with an NPC ally.
So Where do I Find Pink Rathian Eggs?
Pomore Garden in the overworld as well as the Flowery Den and Water Eggs co-op quests are your best bets for finding Pink Rathian eggs. That’s all there is to it!