Reopening a closed board

To reopen a board, first, click on the Boards button from the Trello homepage or directly from http://www.trello.com/my/boards.

Choose the ‘View all closed boards' button. You may need to scroll to the bottom of the page if you have a lot of boards.

Find the board and click " Re-open".

You will need to have been a Board Admin to reopen a board.

When you click re-open, you can choose a different Workspace for that board.

Missing a board? 

The Closed Boards drawer will only show the boards that you are a member of, and Workspace-Visible boards that you did not join will not show on the list.

However, Premium Workspace Admins can reopen a Workspace board they're not a member of by entering the board link directly in their address bar to see the 'Closed Board' page and an option to re-open the board