Skins season 3 will have a whole new cast except for 3 people.
There will be twins and and eastern european character among the british characters.
The 3 characters staying will be Effy, a lot of the show will focus on Effy and her friends.
The other 2 characters staying will be Hannah Murray as Cassie and Mike Bailey as Sid however they will not be the focus of the series and it is unsure wether or not they will be in New York