Bugg and Shiel, who were members of the AIS-AFL Academy program in 2010, join fellow AIS teammates Tim Golds and Sam Darley at the league's 18th club.
All four boys have joined GWS under start-up concessions that allow the club to sign 12 young players born between January and April, 1993.
Shiel, a 179cm midfielder, played most of the season with Caulfield Grammar before joining the Dandenong Stingrays for the later part of the TAC Cup season. He will move to Sydney in 2011.
He said he was blown away by the knowledge that his AFL dream was set to become a reality.
"Obviously leaving my mates and my girlfriend is going to be challenging but in the end I get to be with a whole new group of mates doing what I love," he said.
"I remember sitting next to Kevin Sheedy on the way to South Africa earlier this year for the AIS trip and just listening to him talk about GWS he got me so excited. That was the point when I realised my heart was set on signing."
Bugg, a 184cm utility, also attended Caulfield Grammar but he plied his trade in the TAC Cup with Gippsland Power across half-back, midfield and half-forward.
Also a promising basketballer, Bugg will remain in Melbourne to complete year 12 in 2011, before relocating to Sydney in time for GWS' AFL debut in 2012.
He said the AIS-AFL trip to South Africa had given him a chance to get acquainted with his new club's football staff.
"They were really involved from the outset so I was able to form some great relationships and interact with them," he said.
"I’ve actually been working with [GWS sports science manager] John Quinn for the last six months now and the things he has said about the people around the club just makes me really happy that I get to be a part of this.
GWS coach Kevin Sheedy travelled with Shiel and Bugg on to South Africa year and was thrilled that both players had agreed to join the club.
"What I noticed about the pair of them is their outstanding leadership qualities. They will both be incredibly important to the future success of this football club.
"Dylan and Tom are just another example of the exciting young footballers that are joining Team GWS. With just a month until we start our first pre-season training, this is a very exciting time for all of us."
The pair takes GWS' number of signed players to 13, including fellow priority 17-year-olds Golds and Darley; NSW/ACT zone selections Sam Schulz, Mark Whiley, Kurt Aylett, Anthony Miles, Josh Bruce and Jacob Townsend; NT zone selections Curtly Hampton and Shaun Edwards and rugby league recruit Israel Folau.
