Usage

Spectators can fly, clip through blocks and entities, and view invisible players.

Noclip

Spectators can move through blocks, entities, and other players. Spectators are not noticed by mobs, and do not trigger mob spawning (including from spawners), nor do they prevent mob despawning. When their head is inside a block, they can see through all blocks.

Spectators cannot take damage, as all blows go through them. Lava, drowning, fire, and suffocation also do not affect them. However, they can take damage from the void or /kill.

Commands (including player selectors) can still target spectators.

Flight

Spectators are always flying. They cannot stop flying by landing, as the player will just go through the blocks. The mouse scroll wheel, the sprint key, and the slowness and swiftness effects all affect the flying speed.

GUIs

If you open your inventory while in spectator mode, you cannot interact with any of the items in it. Likewise, viewing GUIs is possible, but it is not possible to interact with them. You also cannot pick any item up. Items in your inventory cannot be used.

If you click a number on your keyboard, you can teleport to a specific player on that server by pressing 1, or you can teleport to a team member by pressing 2.

Seeing invisible entities

Spectators can see other spectators and invisible mobs, as well as themselves using F5. Spectators appear as a translucent disembodied head, and the selected item from the hotbar is also visible. Invisible mobs appear translucent, like when viewing a invisible ally with /scoreboard teams option <team> seeFriendlyInvisibles set to true