Yes, you absolutely need a valid passport to travel via the Eurotunnel (Le Shuttle) from Folkestone to Calais, and subsequently to Paris. Even though you are staying inside your vehicle, you must pass through both UK Exit Checks and French Border Control (Schengen) before you are allowed to board the shuttle. In 2026, this requirement is strictly enforced for all passengers, including children. Since the UK is no longer part of the EU, you must ensure your passport was issued less than 10 years ago and has at least three months of validity remaining beyond your planned date of departure from the Schengen Area. Furthermore, as of early 2026, non-EU/UK citizens (such as Americans or Canadians) may need a valid ETIAS travel authorization linked to their passport. While the Eurotunnel is a "drive-on" service, it is legally an international border crossing, and failure to present a valid passport will result in you being turned away at the terminal, regardless of whether you are traveling for business, tourism, or just a quick day trip.