When you log back in to your Twitter account within 30 days of deactivating it, Twitter automatically reactivates the account and restores everything as it was before. It may take several minutes, but eventually you can see all your tweets again, and you can continue receiving tweets from people you followed. You also get your own followers back, although it could take up to 48 hours to see them all.

After 30 Days

If you wait longer than 30 days, Twitter permanently deletes all your user information, including your followers list. You can create a new account with the same Twitter handle if someone else hasn't already claimed it, but you'll have to start over getting new followers and following other people. None of your old tweets will be connected to the new account.