The city came out on top in the UK with 75 per cent of respondents saying they had some confidence in the way they looked.
A fifth of people surveyed said they loved their bodies and would not make any changes to their appearance.
Residents said their best assets were their eyes, skin and stomachs. However, the rest of the UK rated stomachs as their least-loved body part.
Carried out by cosmetic surgery experts MYA, the survey also found social media was the biggest knock to confidence for people in Portsmouth, but avoiding the sites boosted their body confidence.
Elsewhere, Sheffield was second-most confident city followed by Coventry.
South coast city Southampton ranked eighth.
Across the UK, eyes were voted people’s favourite feature while weight gain was biggest confidence knocker.