Watts has taken over 300 wickets since his Southern Premier League debut in 2012, former Hampshire opener Derek Kenway, playing for Burridge, being his first victim.
Watts, who has regularly been New Milton's top wicket taker, admitted it had been a tough decision to leave the Green & Golds.
"I've played there since I was seven years of age and made my adult debut as a 12-year old, but I felt leaving was the right thing for me to do," he explained.
"Our relegation into Division 2 at the end of last season wasn't much of an influence on my decision, more in terms of living on the island.
"I'm very much looking forward to a new challenge with Ventnor and excited for what we can achieve with the squad we have after a couple of new additions."
Watts, who has played indoor six-a-side cricket for Ventnor on the island this winter, will be joined at Steephill by off-spin all-rounder Dan Cox, who has returned to the cliffside club after six seasons with Lymington.
Ventnor captain Ben Woodhouse said: "George and Dan bring masses of Southern Premier League experience to our side.
"We know what Dan is capable of from his time with us before moving to play in the Premier m Division with Lymington and watching him develop into a decent all rounder has been great.
"Its been great getting to know George over the last few months and it has become clear he will offer plenty both on and off the field."
Drawn away to Amport in the national Village Cup, Ventnor begin their Division 1 programme against promoted Waterlooville on May 4.