2-year old birthday venue

Hi Mhward! We faced the same dilemma with my son's 2 year-old birthday last winter. I read a suggestion to rent a room at the Berkeley Fellowship of Unitarian Universalists on BPN. We ended up renting the Connie Barbour room at BFUU and it was perfect! The room has big windows on each side, a kitchen, and is a large room for hanging out. We hosted around 30 people, about 20 adults and 10 kids, and just had pizza and donuts and music. It was also much more affordable than other room rental options-$45/an hour. They also have a playground outside (it was raining during our party). It wouldn't work for animals, though. Good luck with the party planning!

We just went to Little Farm for a birthday for my son's classmate.

Open park, farm animals, small play structure, and free!

Grab a couple picnic tables and bring some food. Also, bring celery and lettuce to feed the animals.

Jungle Gym is a fun place in Concord I think they are located in the new Veranda mall. Lots of cool things you can do although he won't remember. :)

*Sulphur Creek Nature Center (Hayward Area Recreation & Parks) has lovely woodsy indoor/outdoor spaces, animal exhibits & meet-n-greets, and they offer birthday party packages. This is a native wildlife rehab facility and a learning center that has some very dedicated and knowledgeable naturalists.

*Lawrence Hall of Science, 'Animal Discovery' parties in their downstairs lab area.

*EBRPD Tilden Nature Area's Environmental Education Center's or the Little Farm. This one may be outdoors-only, chk for indoor options. Bundle the kids up and take them around to feed the cows, pigs, chickens, geese and goats, then a walk along the long wooden trail.

EBRPD Crab Cove Visitor's Center, Alameda Island. Search for East Bay Parks Online 'nature party'. This is a lovely indoor area with interactive estuary / bay shore exhibits. Could also do a nature walk along the water.

Finally, just have to give a shout out to the Oakland Aviation Museum near the Oakland Airport. Not very toddler-friendly for climbing/touching, but lots of vintage planes to look at, some interesting flight exhibits, and a large space for a party - both indoors and out.  Tables in the hangar might be a way for you to bring your own airplane-focused games, crafts, and party favors to keep the party-goers content and busy? They have a nice aerospace gift shop too.

I'm in the same situation - looking for good ideas. Two possibilities I'm exploring: I think habitot hosts parties, and might have a good space for this age group. Also, I called the Lawrence Hall of Science - for the under 4 crowd, they will give you a table downstairs for cake etc., and let your group roam the museum that day. (They do more for the over 4s).  

It may be a bit of a drive for you but a few options are Crab Cove in Alameda (free to visit, next to beach, fish tanks) and/or Sulphur Creek Nature Center in Hayward (free to visit, mostly birds of prey, reptiles and a few mammals).  Both are great options and the perfect size for 2-year-old attention spans.  Ardenwood Fram, in Fremont, is another great option (small fee, farm animals).  There is also Little Farm at Tilden (free to visit, farm animals, bring lots of lettuce/celery to feed them) but it can get very crowded.

Enjoy!

I agree the zoo is quite pricey.  Have you looked at the Lindsey Wildlife Museum in Walnut Creek?  Another option for an indoors party (but no animals) is Habitot museum in Berkeley.  It's very child-focused but it's a nice venue where adults can watch their kids and chat at the same time.  It's small enough for 2 year olds but there's lots to do and the rooms are small enough to facilitate small groups of adults chatting while their kids play.  They also allowed you to bring food around the museum which surprised me.  

The Rec Room in Berkeley is popular for toddler birthday parties, though a bit spendy. Parents appreciate it because it's a contained area and they can relax and chat with each other while the kids play. There's also Kids Gym. Rain or Shine used to be an option but they're closed. Albany Bowl is an economical idea -- you can rent a few lanes and have bumpers for the littles. Lawrence Hall of Science also does birthday parties in the cafe, which has a nice view.

I can't help but think an AirBnB is not the best choice for a 2 year old party. 2 year olds tend to spill things, run into things, break things, draw on things, etc. AirBnB's are also not necessarily child safe, so there might be open outlets, things the kids can swallow, etc. You didn't say where you lived, but there are many choices for spaces to host parties. You could do it at a restaurant that has a private room in the back, you can rent a room at a community center, or you can call one of those children's play areas (like Twirl in Alameda, Habitot in Berkeley) and book the space for a few hours. 

Sulphur Creek Nature Center in Hayward! It's a wildlife rescue program and basically a free mini-zoo in a wooded setting. There's a tiny museum, too, perfect for toddlers and preschool. Indoor environs are not classy--"unpretentious," let's say--but comfy and manageable for a group of little kids. The educational staff and programming is wonderful. The birthday parties include an age-appropriate presentation where they bring in live animals to see and touch and learn about (the birthday kid can choose which animals when you book the party). Then you get the kitchen/dining area for an arts and crafts activity, then cake/food (I think you have to bring your own). Cost is very reasonable compared with other options. We did 2 or 3 preschool-age parties there and loved them. https://haywardrec.org/129/Nature---Sulphur-Creek-Nature-Center 

You could consider a train ride somewhere. We had a 2-year-old birthday on the Niles Canyon railway and a 3-year-old birthday riding Amtrak to Sacramento (to go the train museum).  Or meet up a museum that both adults and kids would enjoy, like Cal Academy of Sciences or the Oakland Museum of California.

How about going out to a place where kids can play while adults mingle?  I hear Kensington Circus Pub is like that, though the food can be hit or miss.

https://www.yelp.com/biz/kensington-circus-pub-kensington?osq=kensington+pub

When our kiddo was 3, we did a picnic at the Koret Playground in Golden Gate Park.  There is a great playground and the kids love the carousel.  There's even a hot dog stand if you need some extra goodies.

Instead of airbnb, you could also try peerspace.com. They have rentals, including large spaces, in many unique places around the Bay Area. We used one for our son's birthday in SF a few year's back.