If you want to get the boomerang in Zelda Legend: Link’s Awakening_ on Switch, get ready for long term.
Not only will you need to finish the long business quest that will take you at the end of the map, but you will also need the magnifying glass to see the NPC that gives it. If you did all this, let’s start.
First of all, you will have to head south of the village of Mabe and find a cracked wall near the ocean you can bomb to reveal a cave. When you enter, as long as you have the magnifying glass, a large NPC similar to a dog comes out.
When you talk to the NPC, you will need to exchange one of your objects to get the Boomerang. This can not be any object, but maybe you use the shovel because it is useless after part of the game.
You will be able to recover however the object you exchange against the boomerang, so do not worry. This will cost you 300 rupees, though. At least you have the boomerang now.