Yoku's Island Express

Rinri is located above and to the right of the post office. Speak to him and he'll give you spores that he wants you to plant in five specific places around the map.

1. Above the giant creature in the village. Use the beeline to get to it.
2. To the left of the big monkey holding up the platform in the middle of the map, in the alcove.
3. On the far right of the map, on the cliff above the beach. Drop off from the beeline to reach it.
4. At the end of the beeline that takes you up to the top of the snowy section, the spore spot is on top of the structure on your left from where the beeline ends up top.
5. From the beeline that goes east to west to the Skull Gang hideout, drop off the middle of it and into the water in the gap between the yellow sections. Go left and onto the land there, and then left and drop down. Use the flipper on the left to break through and drop down again, and then use the yellow flipper to launch left, swing across the gap, and into the alcove where the soil is.

After planting all five, return to Rinri to complete the quest and unlock this achievement.