  This paper studies the choosability of signed planar graphs. We prove that
every signed planar graph is 5-choosable and that there is a signed planar
graph which is not 4-choosable while the unsigned graph is 4-choosable. For
each $k \in \{3,4,5,6\}$, every signed planar graph without circuits of length
$k$ is 4-choosable. Furthermore, every signed planar graph without circuits of
length 3 and of length 4 is 3-choosable. We construct a signed planar graph
with girth 4 which is not 3-choosable but the unsigned graph is 3-choosable.
