Looking on the internet deeply has found these results:

I am in bathroom is the most popular phrase on the web.

I am at bathroom 13 results on the web	I am in bathroom 11,440,000 results on the web More popular!
Some examples and use cases from the internet:	Some examples and use cases from the internet:
I am close enough to the bathroom that I don't have to waddle far. No, I am tired of being a slave to your fear of public bathrooms. I am in a damp bathroom full of naked women every day, and I hate it. I am much further from the bathroom. What I am is a grown woman who needs help using the bathroom. I am locked in a bathroom with a baby in a thunderstorm. I am in the bathroom of Barbra Streisand's airplane. I am in a damp bathroom full of naked women every day, and I hate it.	I am in a damp bathroom full of naked women every day, and I hate it. I am locked in a bathroom with a baby in a thunderstorm. I am in a damp bathroom full of naked women every day, and I hate it. I will be needing extra shelf in bathroom. I will be needing extra shelf in bathroom. We need to stop meeting in bathrooms. Listen, I am locked in the bathroom of the honeymoon suite at Cupid's Cabin... I am in the bathroom of Barbra Streisand's airplane.

I am at bathroom

13 results on the web

I am in bathroom

11,440,000 results on the web

More popular!

I am in a damp bathroom full of naked women every day, and I hate it.
I am locked in a bathroom with a baby in a thunderstorm.
I am in a damp bathroom full of naked women every day, and I hate it.
I will be needing extra shelf in bathroom.
I will be needing extra shelf in bathroom.
We need to stop meeting in bathrooms.
Listen, I am locked in the bathroom of the honeymoon suite at Cupid's Cabin...
I am in the bathroom of Barbra Streisand's airplane.