  We calculate the processes $\gamma p \to K^0 \Sigma^+ , K^+ \Sigma^0, K^+
\Lambda$ in three flavor heavy baryon chiral perturbation theory to one loop.
Some low--energy constants are fixed from single baryon properties while others
are estimated by means of resonance saturation. The total cross sections are
comparable with the few existing data points in the threshold region. The
angular dependences of the recoil polarization of the $\Lambda$ and $\Sigma^0$
show most features of the ones measured at ELSA. We also predict the isovector
charge radius of the $\Sigma^+$, $< r^2_V >_{\Sigma^+} = (0.30 \pm 0.03) fm^2$.
