His replacement, Easterby a former Scarlets skipper and British and Irish Lion, has served his apprenticeship under Davies as a defence coach and will now step up to the head coach role.
Acting under Easterby will be backs coach Mark Jones, strength and conditioning coach Brad Harrington and a fresh face in new forwards coach Danny Wilson.
And while Davies admits he leaves with a heavy heart the Gloucester-bound coach insists he's got every confidence in the new coaching set-up.
"It has been a true honour and a privilege to be head coach of the Scarlets and the last four years has been one of the most proud periods of my professional career," said Davies.
"Coming from Trimsaran, to be head coach of the Scarlets has been so much more than a job to me - it has been pinnacle of my Welsh rugby career to date to be able to lead the region that has been such a major part of my life and such an inspiration to me.
"During the past four years I've have worked with real intensity with a talented and committed group of ambitious coaches and players.
"I believe I leave the Scarlets on a very firm footing in terms of results, performance and the development of players and it's great to see that there will be another group of young talented players that have come through the Scarlets system getting their first caps at Wales' game against the Barbarians this weekend.
"My decision is underpinned by my belief that the coaching group at the Scarlets has progressed significantly over the past two seasons.
"Simon (Easterby) and Mark (Jones), with the added impetus of Danny Wilson, will create a talented, dynamic and energetic coaching environment and I have no doubt they will move it forward successfully.
"I wish Simon all the very best and he has my full support in his appointment as the new head coach."
63x46.png){kind=logo}