Pokemon Sun and Moon

Isle Avue

 - The place to boost Happiness and hatch Eggs while you're idling.

The place to boost Happiness and hatch Eggs while you're idling.

 - The place to boost Happiness and hatch Eggs while you're idling.

The place to boost Happiness and hatch Eggs while you're idling.

 - The place to boost Happiness and hatch Eggs while you're idling.

The place to boost Happiness and hatch Eggs while you're idling.

 - The place to boost Happiness and hatch Eggs while you're idling.

The place to boost Happiness and hatch Eggs while you're idling.

Isle Avue is an island consisting of hot spring baths. Pokemon sent there will relax, and their Happiness will go up without you having to do anything. There's no time limit so once you leave them there, the Pokemon will stay until retrieved.

You can also leave Eggs behind here and they will get closer to hatching without you having to walk around at the cost of it taking much longer. Leave behind Poke Beans in the wooden crate to double the rate at which Happiness grows and Eggs get ready to hatch.

Tapping on a Pokemon or Egg will allow Mohn to inform you on its status. The Egg descriptions are fairly intuitive, but Mohn's descriptions of how relaxed the Pokemon are are provided below with a range of their numerical Happiness so you can see exactly what Mohn is saying.

Most Happiness-based evolutions happen at 220 Happiness to give you a benchmark of what you'll usually be aiming for. Max Happiness is needed to max out the power of Return.

Description Happiness Range
"Your Pokemon looked like it had taken all the heat it can handle! But it seems to have perked up now that it's seen your face, hmm?!" You left your Pokemon in Isle Avue for 24+ hours after reaching the previous level, causing Happiness to decrease.
"Your Pokemon seems so relaxed that it would be impossible to be any more relaxed!" 200+ Happiness
"Your Pokemon looks mighty relaxed!" 150 - 199 Happiness
"Your Pokemon looks pretty relaxed!" 100 - 149 Happiness
"Your Pokemon looks quite fond of Isle Avue." 0 - 99 Happiness

It can take a few days to max out the Happiness of your Pokemon, but make sure you check back consistently so that your Pokemon doesn't get heat sickness and lose Happiness because it got left in the hot springs.

Additionally, if you are too lazy to talk to the Happiness Checker NPC in Konikoni City's market, you can put a Pokemon in the hot springs, tap it to hear Mohn's evaluation, and then put it back in the PC.

Isle Avue is one of the more high-maintenance Isles to level up. Here are the requirements:

Isle Level Plain Beans Pokemon in PC
1 60 Beans 60 Pokemon
2 150 Beans 75 Pokemon
3 240 Beans 90 Pokemon

Higher Level Benefits

It shouldn't be surprising to know that Happiness goes up faster and Eggs hatch quicker once the Isle is maxed out since the hot springs water will flow faster.