U's set free
The pair joined the Pool in March on loan and stayed till the end of the season. They have been now been released due to being surplus to requirements at Layer Road.
Stockley made three starts and four substitute appearances for the Seasiders, filling in a right back and right midfield.
Williams managed to make an impression, scoring three times in six starts and three substitute appearances. The pair will now be looking to earn contracts at Blackpool but they might be thwarted by the delaying of the decision about the future of manager Simon Grayson.
Grayson is yet to know if he'll be in charge next season and until then no signing will be made.
Colchester have also released defender Stephen Hunt and striker Tony Thorpe.