Is "I'm in the swimming pool" correct?

[Winwin2011]

At the swimming pool, I heard a domestic helper speaking on the phone, she said "I am in the swimming pool". She was waiting for children. Then she would pick up the children.

I wonder if "I am in the swimming pool" is correct in the above context?

Thanks.

[5jj]

Unless she's actually in the water, 'at' would be more natural,