Since 2002, the GRACE mission provides estimates of the Earth's time-variable gravity field, from which one can derive ocean mass variability. Now that the GRACE mission has come to an end, it is especially important to find alternative ways for deriving ocean mass changes. For the first time, we use kinematic orbits of Swarm for computing ocean mass time series. We compute monthly solutions, but also show an alternative way of directly estimating time-variable spherical harmonic coefficients.