There are 210 tags in Endless Ocean Luminous. This page explains how to unlock new tags in the game.

All About Tags

There are 210 tags available in the game. When you begin the game, you start with the thumbs up tag, the embarassed/angry face, the surprised face, and the sad face, as well as four random tags.

How to Unlock New Tags

To unlock new tags, you need to participate in Shared Dives, and find dive buddies. To do so, press X to look at the map, then go to locations where map squares are appearing. When you get there, look around for bubbles from another diver, then swim to that diver to add them as a dive buddy. Then, when you look at the map, you will be able to see all the tags that your dive buddies have placed. If they have placed a tag that you haven't unlocked, the tag will have a brown background. If the tag is on a salvage item, you can salvage the item to unlock the tag. If the tag is on a sea creature, scan the creature, then look through the list of scanned creatures for the one that has a tag on it. The tags will be shown in the upper-left corner of the screen.