The new statistics come as a staff body praises the contribution made by "hugely talented workers from around the world" to England's healthcare system.
The figures, from NHS digital, show Surrey and Borders Partnership NHS Foundation Trust employed 511 staff from outside the UK as of June 30 – or 17.3% of all staff at the trust who declared their nationality.
Of them, 217 (7.3%) were from the EU or European Economic Area, and a further 294 (9.9%) were from the rest of the world.
The ratio of foreign to UK staff at Surrey and Borders Partnership Trust was comparatively low compared to NHS trusts across England as a whole, where 21.5% of staff are non-UK nationals.
These figures were based on the total headcount of staff working at the trust, rather than the equivalent full-time employees.
Saffron Cordery, interim chief executive of NHS Providers, the membership organisation for NHS trusts, said the figures show “just how much our severely understaffed NHS relies on dedicated people from all over the world to deliver high-quality care to patients”.
As of June, there were 60 doctors and 96 nurses from outside of the UK working at Surrey and Borders Partnership Trust.
Ms Cordery continued: “The stark reality is that the NHS just doesn’t have enough staff, putting patients’ safety at risk by affecting the care that overstretched staff can provide.
“With vacancies at an all-time high across health and care services – 132,000 in trusts in England alone – we desperately need a long-term, fully-funded workforce plan for the NHS from the Government to invest in growing the staff we recruit from within the UK, alongside valued recruits from abroad.”
Of the 125,741 full-time equivalent hospital and community health service doctors in England in June 2022 whose nationality was known, 42,531 (33.8%) were non-UK nationals, up from 25.9% in December 2016.
There has been a similarly sharp jump in the proportion of nurses and health visitors who are non-UK nationals, which now stands at a quarter of the total, up from around one in six in December 2016.
Caroline Waterfield, of the workforce organisation NHS Employers, said: “The NHS benefits greatly from hugely talented workers from around the world.
“The recent focus on additional recruitment of international nurses has resulted in a significant change in the profile of the NHS nursing workforce – we have also seen an increase in the numbers of individuals undertaking the nurse degree apprenticeship and undergraduate nursing programmes."
A Department of Health and Social Care spokesman said: “International recruitment is only one part of our plans to grow the NHS workforce, and the supply of homegrown staff is increasing.
“NHS England have also been commissioned to develop a long-term workforce plan to help recruit and retain more NHS staff.”