Customs formalities around the world differ based on which country you are in and where your sailing vessel is registered.
If customs and/or immigration clearance are required, the crew must remain on board the vessel until the skipper has completed the formalities and the Q flag has been taken down – rya.org.uk
Customs Formalities
Outside the UK
If you are outside the UK and on a UK registered vessel, the above rule may apply depending on whether both your departure and arrival ports are within the EU. Flying the Q flag and contacting customs and/or immigration depends on if it is within the EU or further afield.
If your vessel remains within the EU and you do not have anything to declare, you do not need to fly the Q flag. However, you should still be prepared to present your paperwork and passports for everyone on board if asked.
If you are sailing outside the EU, customs and immigration formalities differ depending on the country. If you are unsure of the procedures, simply fly the Q flag upon entering territorial waters. On arrival, you should visit customs and immigration to get clearance for both the boat and crew. Nobody on board should leave the boat for any reason. This is sound advice and will avoid any misunderstandings!
Arriving in the UK
Credit: rya.org.uk
If you fall into the category of a private individual who is sailing your pleasure craft to and from the UK, Customs Notice 8 explains the customs requirements you must adhere to. Customs Notice 8 describes the customs procedures for arriving and departing the UK. It provides details on temporary importation (for pleasure craft from outside the EU) and how to prove the VAT status of your vessel. You can downloaded this from the gov.uk website or contact the HMRC National Advice Service on: +44 3002 003700 to request a copy by post.
If you sail into the UK straight from an EU country, you do not need to fly your Q flag or notify customs of your arrival. However, you should contact customs/immigration if you have goods to declare or non-EU nationals on board.
If you are sailing into the UK straight from a country outside the EU (such as a transatlantic trip) you must fly the Q flag from 12 nautical miles of the territorial waters limit. Next, report to customs by telephoning the National Yacht Hotline on +44 3001 232 012 or +44 8457 231 110. Notice 8 has details of the requirements for the completion of form C1331.
Departing the UK
If you are leaving the UK and going straight to an EU country, you currently do not have any formalities to complete with UK customs.
If you are leaving the UK and going directly to a non-EU country, you must tell customs of your plans by using form C1331.