Appointed in May as the successor to Gus Williams, the 47-year-old stood down on Saturday night within hours of the club's 0-0 draw at Ilkeston FC's New Manor Ground in the top flight.
Hoskin, who had not been helped by an injury hit squad, secured just three wins in 16 league and cup outings and left Llanelian Road with the club fifth from bottom on 13 points.
Assistant-manager Phil Staley has also resigned with senior players Rob Hopley and Mike Lea set to take charge of team affairs on Tuesday night when the Seagulls travel to Skelmersdale United.
Departed: former manager Ashley Hoskins
In a statement confirming Hoskin's exit, chairman David Titchiner set a deadline of 5pm next Thursday (0ctober 15) for his potential successors to contact the club.
Paying tribute to Hoskin and explaining the club's decision, he said: "Colwyn Bay Football Club announce that they have parted company with manager Ash Hoskin tonight by mutual agreement, and that head of recruitment Phil Staley has also resigned.
"After a very promising pre-season it is sad that things have not worked out as everyone would have hoped, with results on the field being disappointing, but we thank both Ash and Phil for all the hard work they have done over the last five months and wish them both all the very best in the future."
Potential candidates should send their footballing CVs with a covering letter to: info@4crosses.co.uk.
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