To fly from london to ireland do you need a passport?

Yes, you need a passport to fly from London to Ireland. Ireland is a separate country from the United Kingdom, and as such, you need to show your passport when you enter the country. You will also need to present your passport when you check in for your flight at the airport.

If you are a citizen of the European Union, you can use your national identity card instead of a passport to enter Ireland. However, if you are not a citizen of the European Union, you will need to present a valid passport.