Most preschools only accept students in the fall, and require kids to be 2. You’re searching at the right time though for fall registration!

Look at churches. That is the most common part time option like this.

While outside of the areas you mentioned, Ridgemont Montessori School in McLean has a Toddler program for children, 18 months to 3 years of age, 5 mornings/week.

Yes, there is totercise at the MCLean Racquet and Health club. It’s great!

He can go to a 2's class in September, I would wait until then. Most preschools don't take kids mid year.
They do start registering for Sept now though,

OP here. Understood - does anything like this exist? I am not looking for full day childcare - just a few hours in the morning every day for socialization. Thanks

I think when they are that age, it's just a "playgroup" or part-time daycare. Preschool programs typically begin for 2s.

My son is 21 months old - we are looking for a part time program (like from 8 or 9am until 12 or 1pm). Every day or a few days a week is fine. Does anything like this exist in the Vienna/Oakton/Fairfax area?

Thanks!!!