If you choose to use Arbitrum's traditional path instead of a fast exit bridge, you will have to wait ~8 days before you can claim your funds.
If you want your funds faster, we recommend using a fast exit liquidity provider like Hop, Connext, Across, Celer, or Maker.
Why do I have to wait 8 days?
This is how all optimistic rollups work. Optimistic rollups use something called fraud proofs in order to keep participants in the network honest. There is a "challenge period" for these proofs. When one party submits a claim about the state of the chain, another party has ~8 days to challenge that claim.
If you'd like to read more about the technical details of Arbitrum, see Inside Arbitrum.
If you're more of a visual and auditory learner, watch our video about proofs.