Tulletha, who learned yoga in Rishikesh, India -- "the yoga capital of the world" -- said she wanted to share "a bit of spice" with her home town.
"After India, Masterton seemed sterile," she said.
"I was driving down the main streets and noticed how wide and empty they were -- in India, the streets are so tightly packed, and there's all this colour and vibrancy.
"I thought we needed a bit more spice and culture."
She befriended Karina, who wanted to start a yoga-based group to help people build networks and form friendships.
"Yoga isn't just a physical practice; its philosophy is about connection," Karina said.
"In a small town, is that not what we're known for -- making meaningful connections?"
The women began holding yoga classes for a koha at the Wairarapa Community Centre, the Education Centre and the YMCA.
They later held outdoor yoga sessions at Henley Lake and Queen Elizabeth Park -- which attracted a following.
"People would walk past and be curious -- and, the next week, they'd join in," Karina said.
"We've had everyone from eight-year-olds to mothers with newborns wanting to take part."
The collective has hosted numerous workshops, including a hula hoop fitness session, a belly dance lesson from Wellington teacher Ziva, massage therapy demonstrations, and an information evening on alternative health.
Unexpectedly, Karina said, one of the most popular events has been the monthly "108 Aums" -- where people gather and chant "aum" 108 times, by the light of the full moon.
"It sounds a bit kooky, but people keep coming back -- it clicks for them."
The women say they enjoy seeing new friendships form from the yoga mat.
"Before each class, we get people to introduce themselves to someone they haven't met -- you find you can have lots in common with the person on the mat next to you," Tulletha said.
"You're not just going to a class and sitting in your own bubble."
For more information, email theopensoulcollective@gmail.com, or go to www.facebook.com/theopensoulcollective.