The duo have kept the Edinburgh outfit up in a competitive BT Premiership this season after winning BT National League Division One last year, but the club are set to take a new path.
Di Rollo, pictured, who earned 21 Scotland caps, become head coach in 2010. Taylor, who won 66 Scotland caps, joined the club in 2014-15 as a player and has been involved in a coaching capacity for the last two years.
Watsonians president Keith Watters said: “I would like to put on record my thanks to both Marcus and Simon for the hard work they have put in over the last few years.
“To gain the club promotion from a tough second tier was a highlight while this year the team have shown they can compete in the BT Premiership and play a brand of rugby that entertains spectators.
“They leave a squad that is hungry to improve in the coming years and everyone at the club wishes Marcus and Simon well in the future.”
The club has said that a new coaching set-up will be announced in due course.