Yes, it is entirely possible to do a day trip from London to Edinburgh, Scotland, thanks to high-speed rail connections. The journey from London King’s Cross to Edinburgh Waverley takes approximately 4 hours and 20 minutes on LNER’s "Azuma" trains. A typical itinerary involves taking a very early train (around 7:00 AM), arriving in the heart of Edinburgh by 11:30 AM, and spending 5 to 6 hours exploring landmarks like Edinburgh Castle and the Royal Mile before catching a return train around 5:30 PM. While it makes for a long day (roughly 9 hours of travel), the scenic route through the English and Scottish countryside is a major part of the appeal. For those who want more time "on the ground," flying from London Heathrow or Gatwick to Edinburgh is an option, but when factoring in airport security and transit times to the city center, the train is often more convenient and "stress-free" for a single-day excursion.