This incredible milestone includes first, second and booster vaccinations.
Today’s data shows that 3,008,220 vaccinations have been given in total including 428,461 booster doses.
This means that 82.7% of the eligible population in Sussex have had their first dose, 76.5% have had their second dose and 68% have had their booster.
It comes as the number of appointments has been significantly increased for booster vaccinations for the coming weeks through the National Booking System website and 119, and local booking systems.
More than 13,000 additional appointments a week have been arranged, including 2,800 more per week at Churchill Square in Brighton, 1,200 in Eastbourne, 500 more in Chichester, and GP led services are adding extra days and hours to their sessions to make it as easy as possible for people to receive their booster.
The Covid-19 vaccination programme started on December 8 last year, and since then vaccinations have been provided in hospital hubs, vaccination centres, vaccination services and mobile vaccination teams.
Across Sussex there have been more than 40 vaccination sites, with thousands of people involved in the programme, from vaccinators, to administrators, to volunteers, to community partners including transport providers.
At the same time, flu vaccinations are also underway at GP practices, pharmacies and some Covid-19 vaccination sites. To date, more than 450,000 people have had their flu vaccination across Sussex.
Amy Galea, senior responsible officer for the Sussex Covid-19 vaccination programme, said: "It is fantastic to reach this milestone with over three million Covid-19 vaccinations given across our communities in Sussex – and just weeks before the one year anniversary of the programme.
"This is a real collective effort of everyone involved in the programme, and is testament to the amazing commitment and dedication of our vaccination teams to roll out this vaccine to our local population and make sure they can receive this vital protection against Covid-19.
"With winter fast approaching, all of our teams are stepping up their efforts and making sure that there are as many options as possible for people to book and receive both their booster – or their primary doses (first or second vaccines).
"They are also working hard to make sure people their flu vaccination, which is just as important to protect people this winter. It is never too late to come forward.
"Vaccination really is the best way to protect yourself and those around you, especially elderly relatives and those with low immunity."
This week the vaccination programme has extended so that 40 to 49-year-olds are now eligible for a booster vaccination, and 16 and 17-year-olds are recommended to have a second dose.
Both are expected to be able to start using the National Booking System from next week to arrange these vaccinations.
If you are eligible and you have not yet received your vaccination, visit Book a coronavirus vaccination - NHS (www.nhs.uk) or call 119 to arrange your appointment.
New appointments are being added each week, and future weeks are being opened up regularly. If you can’t see a local appointment please keep checking.
You can read more about the Covid-19 Vaccination programme in Sussex, including FAQs about the vaccines, by visiting Sussex COVID-19 Vaccination Programme | Sussex Health & Care Partnership (sussexhealthandcare.uk).