Catan and each of it's expansions has an accompanying extension that expands the game from 3-4 players to 5-6 players. These extensions come with an additional rule allowing an additional build phase for all players between player turns, but no trading with each other or the bank.
The extensions are:
- Catan: 5-6 Player Extension
- Catan: Seafarers 5-6 Player Extension
- Catan: Cities & Knights 5-6 Player Extension
- Catan: Traders & Barbarians 5-6 Player Extension
- Catan: Explorers & Pirates 5-6 Player Extension
4th Edition Edit
Extensions come in small boxes, half the height, width and thickness of their 3-4 player counterparts. The title and artwork are horizontal along long part of the box.
5th Edition Edit
Boxes are now the same length and height of their 3-4 player counterparts, but a little thinner. This makes them easier to stack and keep with your Catan collection. The title and artwork have been rotated since 4th Edition and is now horizontal along the short end of the box. In addition The Settlers of Catan: 5-6 Player Extension was renamed Catan: 5-6 Player Extension to match the new name for the base Catan game.