The super-fit mum-of-three caused a stir last year after a Facebook campaign in which she said women shouldn't be 'proud' about flaunting their fuller figures but should instead be proactive about trimming them down.
At the time, she said: "We need to change this strange mentality we are breeding in the U.S. and start celebrating people who are a result of hard work, dedication and discipline.
"I'm not bashing those who are proud and overweight, I am empowering those who are proud and healthy to come out and be the real role models in our society."
On the back of the incredible response to her campaign, the 33-year-old California set up 'The No Excuse Mom Group' - a collective of mums dedicated to juggling childcare with working out.
Maria wrote on her website: "We have free workout locations throughout the world. We have life, stress, work, kids, responsibilities and obligations.
"We struggle making time for workouts, we splurge on cookie dough and enjoy (and often need) a glass of wine. That's life. And that's completely okay. Balance is one of the keys to success."
This led to her first swimsuit calendar last year, featuring fit mums, which was so successful she's back with another photo spectacular for 2015.
The new calendar features Maria and 24 mums in bikinis and swimwear striking a variety of poses as they work out on beaches, in the pool and with their kids.
Each of the women are, according to Maria, 'real, every day moms who transformed themselves through fitness'.
She said: "We asked our mothers to show the world what an every day mother looks like, without covering scars, stretch marks, or cellulite.
"Health does not look the same on everyone, and it was important for our daughters and sons to see that beauty and fitness comes in all shapes and sizes."
Explaining her philosophy behind the No Excuses campaign, Maria said: "My mother has struggled with weight her entire life and when I was little (growing up and comparing my body to my 2 younger sisters) it seemed my bone and body structure was more favorable to my mom's genetics.
"This realization made me aware of my food intake and activity output at a young age. I saw first-hand how difficult it was to deal with diabetes, heart disease, high blood pressure and kidney failure.
"However, let's say I did have great genetics, I've always believed 30Slideshow-84714%