The 41-strong squad will arrive in New Zealand tomorrow, with their first match on Saturday against a Provincial Barbarians XV.
They then play almost every three days, touring around the country playing five more games before the first Test at Eden Park on June 24.
The squad enjoyed one final photo in England before setting off for the other side of the world, as they soaked up the experience by taking selfies on Monday morning.
Stuart Hogg, Conor Murray and Rhys Webb all snapped pictures with their phones as the Lions stood out on the steps - with coaches posing towards the bottom of the ramp.
On board the plane, the stars looked to be enjoying themselves as they smiled and offered thumbs up to the camera before the long-haul flight to New Zealand.
Hogg and Sexton in particular looked excited for the trip as the players settled in for the flight - the Lions' first journey to New Zealand since 2005.
And the tour's mascot - Billy the Lion - was even permitted a photo in the cockpit alongside pilot Steve Ager and Lions captain Sam Warburton.
Earlier Maro Itoje was pictured checking in for the flight clutching onto Billy - who has his very own passport complete with a paw print for a signature.
At 22 years old, Itoje is keeping up the tradition of the tour's youngest player taking care of Billy, after Hogg was tasked with the same responsibility in 2013.
The tour's official Twitter account joked that Billy had cleared passport control and was all set to board the flight with the rest of the squad.
