Mercer Slough Environmental Education Center

A partnership with the City of Bellevue, offering nature-based programs for all ages.


Polliwog Preschool Program Details

Polliwog Preschool

Session Times

Children may enroll in one of the following sessions:

3-day morning
Meets Monday/Wednesday/Friday, 9 a.m. – noon
For children who are ages 3 or 4 by the beginning of the school year.

2-day morning
Meets Tuesday/Thursday, 9 a.m. – noon
For children who are ages 3 or 4 by the beginning of the school year.

4-day afternoon
Meets Monday – Thursday, 1-4 p.m.
For children who are ages 4 or 5 by the beginning of the school year.


  • 3-day morning: $3,942 per year or $438 per month
  • 2-day morning: $2,772 per year or $308 per month
  • 4-day afternoon: $5,355 per year or $595 per month

Full tuition payment is encouraged prior to the first day of preschool. Families may also pay tuition in nine monthly installments via credit card or check. A non-refundable deposit in the amount of one month’s tuition is due when registering your child. The deposit will cover your May/June tuition.

Frequently Asked Questions

Do you really go outside every day?

Yes! Unless there is a thunderstorm or other severe weather, we go outside for at least part of the day. We believe that there is no bad weather, only the wrong clothing, and we’re happy to give parents advice on what kinds of gear will keep their children comfortable.

How old does my child need to be?

For the morning classes, children must be either 3 or 4 years old by August 31 prior to the start of school. For the afternoon class, children must be either 4 or 5 years old by August 31.

Is the afternoon class the same as kindergarten?

No, the afternoon class is still a PreK program. The afternoon class meets more frequently, and has older children, which means they’re able to do more in-depth nature studies. Families choosing to wait an extra year before enrolling their child in kindergarten are encouraged to apply, however, the class is not intended to be a replacement for kindergarten.

How do you keep kids safe outdoors?

Polliwog teachers are experienced environmental educators with years of practice keeping children safe outside, and we’ve developed thorough safety policies to support them. We have a small class size and superior teacher-student ratio: 12 children and two teachers per class. There is always at least one additional teacher on site who can also quickly join the group if needed. All of our staff are trained in first-aid and CPR, and carry a first aid kit and emergency contact information on all hikes. To learn more, come take a tour and we’ll be happy to talk about specific safety practices (“take a tour” links to the “visit us” page)

Can parents volunteer?

Yes, we welcome parent volunteers. Interested parents can complete Pacific Science Center’s volunteer background check and application process. We ask that parents wait until after the first month of school to volunteer, so that children have the opportunity to adjust to preschool and make friends independent of family.

How do you help children prepare for kindergarten?

We use the Bellevue School District’s kindergarten readiness guidelines when designing our curriculum. Our daily activities promote early literacy through reading stories, signing songs, recording our discoveries in journals, and practicing new words. Mathematics learning takes place when counting, comparing, sorting, and ordering our nature finds. Academic learning is only a small part of kindergarten readiness, so we spend much of our time building social and emotional skills by sharing and taking turns, using words to solve conflicts, and encouraging children to put on their outdoor gear independently. Caring for the world around us is a fundamental part of our philosophy, and interacting with living nature helps us build empathy. As with all Pacific Science Center programs, we strive to ignite curiosity by encouraging children to ask questions, make observations, and persevere even when something is difficult.

What about toilet training?

Our unique site means that children need to be potty trained prior to the start of the school year. Children who are potty trained know when they need to go with little or no prompting, and handle most aspects of toileting with minimal assistance, including wiping. We understand that outdoor gear can make toileting more challenging, and can help children manage their rain gear when needed.

We recognize that children of differing abilities may toilet at different times in their development, and are committed to working with families of children with special needs in order to be as inclusive as possible. For more information, please contact us.

What Our Families Say

“Polliwog Preschool has been the absolute best experience for my child and our family. It has exceeded out [sic] expectations time and time again. Sometimes I wonder how they have time in just three hours to explore nature, create art projects and learn so much. Caroline and Erica are incredible educators and have really created something special. I recommend to this school to everyone I can!”

“ Our child loved every moment of preschool.”

“[I]n early grades there’s too much emphasis on rote and not enough emphasis on first-hand understanding the world around us. Especially in the modern world where we’re increasingly isolated from it. Polliwog strikes a perfect balance.”

“I will miss hearing [my child]’s stories about hikes, slugs, and all the wonderful things she has learned. I will always be thankful she is able to hold a centipede, beetle, and spider and gush over how cute they are.”

“Overall, very professional experience, what I would expect from the Pacific Science Center. What a great service you are providing for the community. I wish every child had a chance to experience this!”

“Polliwog was such a great experience. I’m sure it will be one of our daughter’s favorite childhood memories. We really enjoyed the weekly newsletters and appreciated the time put into them.”

“Going to Polliwog was probably the best decision I have made for [my child].”

If you don’t hear from a Polliwog teacher within 2-3 days, please resubmit your application or contact Caroline Cook at



Mercer Slough Environmental Education Center