One in 34 Dyfed Powys police officers identify as gay or lesbian, early gender figures suggest.
Although the head of the National LGBT+ Police Network said the true numbers in England and Wales are likely much higher, he said police forces should be representative of their communities.
A Freedom of Information request sent by the PA news agency asked Dyfed-Powys Police for a breakdown of the sexual orientation of its more than 1,000 officers in November.
Of the 766 people who responded when collecting the staffing snapshot figures, 22 (2.9%) said they were gay or lesbian.
There is wide variation in the proportion of LGB officers across the 26 police forces in England and Wales who responded to the request and had data for at least half of their officers.
The highest percentage of officers identifying as gay or lesbian was in Sussex (7.2%), while the lowest was in Lincolnshire (2.3%).
Data follows damning findings from inquest into victims of serial killer Stephen Port, in which grieving family members and friends said prejudice, lack of LGBT officers in Barking and Dagenham and a failure to engage with the gay community meant crucial clues were missed.
Chief Inspector Lee Broadstock, co-chair of the LGBT+ network representing gay, lesbian, bisexual and trans officers across the country, said: ‘If we’re not representative of our communities, we don’t understand that community.
“You have to understand what communities need to give people fair policing.”
The figures showed that the vast majority of officers at Dyfed and Powys (96.2%) are straight.
Meanwhile, 0.8% identified as bisexual and less than 1% said they preferred to describe themselves.
The proportion of officers identifying as bisexual is the lowest of any force – along with Suffolk.
Mr Broadstock said the actual number of LGB officers in each force would likely be higher, with no sexuality recorded for 61,000 out of 131,000 officers in the two countries.
Mr Broadstock, who said he had previously experienced homophobia among colleagues and members of the public, added: ‘Sometimes they don’t trust what their HR force is going to do with their answers – are they going to be treated less favorably in the future when it comes to promotions?
“Without a doubt, Port has shed light on the cultures within the police that are not welcoming environments.
“It’s sad that it’s still the case sometimes, but the situation is absolutely improving.
“If you had tried to get these numbers 20 years ago it would have been a very different story – I doubt you would have gotten any data.”