Whether fundraising, helping to build and maintain facilities or encouraging people to get involved in - and stay in - the sport, volunteers are the foundation of the game at local level.
Here are three examples of people really making a difference in their communities:
Five years ago, visually impaired (VI) tennis coach Wendy Glasper set up North East VI Tennis Club - incorporating sites in Jesmond, Sunderland and Stockton - and since then has worked tirelessly across the region to promote the sport to people who are blind or have sight impairment.
A qualified LTA level 2 coach, Wendy is also an accomplished player herself, finishing runner-up in her sight category at the National VI Championships at Roehampton in 2015. And she continues to inspire youngsters and adults to play the sport competitively or just for fun.
"It's so rewarding giving back to a sport I love and see our players grow in confidence, gain new friendships and improve their mental wellbeing," she says.
"One of our members is completely blind and has just won his first tennis competition in Newcastle. For me, knowing that our VI tennis sessions enabled him to achieve this is just brilliant.
"For anyone looking to volunteer, I would say just do it! If you are passionate about something, you will inspire others to help you and I'm so thankful for the people I work with for bringing VI tennis to more communities in the north east."
This really is a story of building facilities from the ground up. In November 2015 there were no useable tennis courts in Hingham, a small Norfolk market town of 1,000 houses. Fast-forward to October 2016 and Hingham has a thriving tennis club with 200 members.
How did this happen? Three volunteers - Emily Cary, Lindsey Read and Simon Underhill, none of whom had even been in a tennis club before - raised £91,000 from Sport England and local businesses to renovate the derelict courts next to an existing sports hall into two hard courts and a well-appointed clubhouse.
The club now delivers coach-led evenings of activities to the local youth club - free of charge - plus a weekly Cardio Tennis session, which the local slimming club attends.
"We went out to local fairs, shows and schools to understand if this was something people would be interested in," explains Lindsey. "It was a great chance to explain to our community what we'd like to do and rally support for our plans.
"After a hard year of gathering evidence of need, impact and sustainability, we applied for funding from Sport England and got the maximum bid of £75,000. We then gathered funds from nine other local charities and trusts, plus a crowdfunding campaign and business sponsorship to go ahead with the project.
"It was a long and challenging process, but it's fantastic to give something back to the community and for anyone thinking of volunteering, just do it - don't underestimate what you'll get out of it."
It's fair to say 17-year-old John Heppell has grown up at Durham Archery LTC. He joined aged four and has been volunteering at the club for the last six years.
Now assistant coach on the club's Junior Coaching Programme, he helps in junior coaching sessions (ages 4-16) on Friday evenings and Saturday mornings, year-round, whatever the weather.
Parents have been glowing in their assessment of John and his work with their children, with his infectious enthusiasm for the game translating into good retention rates for the club and real progress in his students' aptitude for the game.
"John has always been very shy, and every school report mentions that he is very quiet," says mum Christine. "Volunteering has helped him come out of his shell and be more confident.
"He has inspired our current generation of young members with his coaching skills and, as a result, we now have other young teenagers keen to assist in the club Junior Coaching Programme on a Saturday morning."
Find out more about the British Tennis Awards and how you can volunteer for British Tennis here.
And for more on National Volunteers Week, go to volunteersweek.org/about or visit the NVCO (National Council for Voluntary Organisations) website, here.
National Volunteers Week runs from 1-7 June and tennis' governing body - the Lawn Tennis Association (LTA) - has shortlisted around 1,200 volunteers whose efforts will be recognised at the British Tennis Awards, during Wimbledon fortnight.