A brand-new feature called Munchlax’s Nap Island is coming to Pokémon Sleep on July 19 at 9 p.m. local time as part of the game’s Third Anniversary celebration. Nap Island is a new location where players can send one helper Pokémon to spend time with Munchlax and gradually earn EXP while away, accumulating 150 EXP per day and recovering 15 Energy every 24 hours, with Pokémon receiving the full amount of accumulated EXP after staying for at least seven days. The feature unlocks after players register 35 sleep styles in the Sleep Style Dex, and Pokémon can continue earning EXP beyond the initial seven-day period, while any excess EXP earned by a helper Pokémon at its maximum level will instead be added to the EXP Bonus Gauge.
Pokémon assigned to Nap Island cannot be added to the current helper team or have items used on them until they return, and they will not recover Energy through sleep reports while away. The update also introduces the new Relaxing Nap Ticket item, which rents a Relaxing Set for seven days to increase EXP gains by an additional 450 EXP per day, with the first ticket being awarded free the first time players send a helper Pokémon to Nap Island. In addition, Munchlax will periodically use Pickup to collect items such as Dream Shards and Pokémon Candies while a helper Pokémon is visiting the island, presenting everything collected in the Pickup Box as a souvenir when the Pokémon returns.
Source: Official Pokémon Sleep news and PokemonSleep.net