A stage tool and a method for stage cementing a wellbore annulus. The method includes: running into a wellbore toward bottom hole with a tubing string to a position in the wellbore; setting the tubing string in the wellbore to create the wellbore annulus between the tubing string and a wall of the wellbore; opening a cementing port through a side pocket structure positioned alongside the tubing string; pumping cement through the cementing port; and closing the cementing port to hold the cement in the annulus.