That can’t happen though because they’d be without a currency in the interim period and it’s also baked in to the EU’s treaties to make this difficult else places like Catalonia and the Basque Country would break away and join the EU, so there are barriers in place to make this less than quick or easy.
It would be rather foolish, but they can continue using the GBP. Or they can start using the Euro before joining. They wouldn't be able to mint their currency, but plenty of small (often island) nations use foreign currency already.
Scotland is already a separate country, technically speaking, so I don't think it's comparable with the Basque situation. Furthermore, with the UK leaving the EU, they've opened doors that non-EU members can't use to work around such issues.
I don't think it'll happen soon, but the desire for independence does seem to be there to a significant extent already: https://www.telegraph.co.uk/politics/2026/09/13/irish-scots-...
The largest problem for an independent Scotland trying to join the EU would probably be that the EU doesn't just let anyone join. You need to have a strong enough economy and a grip on national debt to join.