The National Trust (NT) said three chicks had now fledged from one nest and another five from a second nest.
An adult bee-eater was first spotted at Wydcombe on July 15 by NT dragonfly survey volunteer Dave Dana. And chicks were first sighted a month later on August 15.
There were originally thought to be nine chicks but one has not survived.
Dave Dana, a NT volunteer, said: "I'd just come from counting golden-ringed dragonflies at a stream and I thought 'that bird looks a bit different!
"Its flight path seemed almost triangular. I didn't really appreciate the bird until I got home and looked at the photos. I'd always wanted to see a bee-eater in this country but I never thought it would turn out to be a major wildlife event."
Many volunteers and staff gave up their free time, and often their nights, to assist with vital 24-hour surveillance to protect the birds and their eggs.
More than 3,000 people made their way to the Island to catch a glimpse of the colourful visitors.
The birds are expected to leave for Southern Africa within the week. They will fly thousands of miles across France, Spain and Gibraltar to reach their winter feeding site.
Normally found nesting in the Mediterranean, bee-eaters were last recorded successfully breeding in the UK in 2002.
Matthew Oates, NT wildlife adviser, said: "Bee-eaters are usually faithful to breeding sites so we’re hoping that they return in 2015, but this will be dependent on weather and other perils of migration that birds face."
Keith Ballard, the site manager at the RSPB’s Brading Marshes reserve, said: "To have four bee-eaters arrive on the IW, nest safely, and return as 12 is a fantastic result, exceeding all expectations."
See more pictures and videos below, courtesy of the National Trust.
Isle of Wight bee-eater and chick. Picture courtesy of National Trust/IanRiddett.
Isle of Wight bee-eater adult and fledglings. Picture by National Trust/Danny Vokins.
Insect-eating birds, feeding on a wide variety of flying insects including wasps and bees.
Breathtakingly colourful birds with turquoise underparts and tail, bright yellow throat, chestnut head and back, green eye markings, and black eye stripe.
They lay their eggs (clutch of 4-9) in holes between 50 and 275 cm in length, excavated by the birds in soft earth.