End portals allow a player to teleport to the End Dimension, home of the Ender Dragon. They are found in strongholds, of which there are only 3 per world. They cannot be created by a player in survival mode, without the use of mods.
The portal can be recreated in creative mode by clicking the scroll button on your mouse, while looking at a portal frame block, this’ll put a portal frame block in your current selected hotbar slot.
The End portal consists of 12 blocks in a 5×5 square without the corners. Each portal frame block requires an eye of ender for the End portal to be activated.
Finding the portal requires a decent supply of eyes of ender, plus an additional supply to activate the portal. By firing an eye of ender, the eye will fly up in the air and towards the End portal. This eye of ender will then either fall back on the ground or explode in a small burst of particles.
Using enough eyes of ender will eventually lead the player to the portal, though this can take a very long time. When a player is on top of the portal, on any altitude, any eye of ender shot into the air will go straight down into the ground, which is usually the only indication of a stronghold.
Once you’ve reached the portal, eyes of ender will have to be placed in each end portal frame block. There are a total of 12 frame pieces, though some pieces usually already have an eye of under inserted.
Once every portal frame piece has been filled with an eye of ender, the portal will activate. Simply jumping in will teleport you to the End without a risk of falling into the lava below.
Any contact with the active part of an End portal will immidiately teleport the player.
Unlike the Nether portal, the End portal is a one way only teleportation method. Once a player enters the portal, the player will immidiately be teleported to the End without any time to back out. The player will spawn on top of a generated, 5×5 sqaure of obsidian, which could be floating in the air or underground.
Breaking a portal frame block of an active portal will not deactivate it. This is only possible by using mods, as portal frames are as strong as bedrock. This also means a portal cannot be deactivated in any way, unless you use mods to break the teleportation pieces themselves.
The active part of an end portal emits a light of level 15, though this is of no real use as it cannot be picked up without the use of mods.
End portals can be made by a player in creative mode or using mods, however, the portal can only be activated if the last portal frame to receive an eye of ender is positioned correctly, which is placed from within the circle, facing outwards.
The active part of an End portal can also be obtained through mods, this can be placed and will instantly teleport any player who touches it, no matter the size of the portal. This is sometimes used as a trap on multiplayer servers, though most servers don’t allow players to have indestructable blocks. Note that these blocks cannot be placed in the End.