Scarlett Johansson -- I'm Ready For Motherhood ... On BOTH Coasts!

Scarlett Johansson is looking to rekindle an old romance ... not Ryan Reynolds -- looks like she's moving back to L.A.

Real estate sources tell TMZ ... "The Avengers" actress scoped out a Spanish-style home last weekend in Los Feliz ... the same area where she and Reynolds lived. When they broke up, they sold the house.

Johansson is currently living in NYC with fiance Romain Dauriac.

Our sources say she passed on the $2.9 mil Los Feliz property after spending close to an hour there. It just wasn't private enough for her.