Sea level is an Essential Climate Variable (ECV) that has a direct effect on many people through inundations of coastal areas, and it is also a clear indicator of climate changes due to external forcing factors and internal climate variability. Regional patterns of sea level change inform us on ocean circulation variations in response to natural climate modes such as El Niño and the Pacific Decadal Oscillation, and anthropogenic forcing. Comparing numerical climate models to a consistent set of observations enables us to assess the performance of these models and help us to understand and predict these phenomena, and thereby alleviate some of the environmental conditions associated with them. All such studies rely on the existence of long-term consistent high accuracy datasets of sea level. The Climate Change Initiative (CCI) of the European Space Agency was established in 2010 to provide improved time series of some ECVs, including sea level, with the purpose of providing such data openly to all to enable the widest possible utilisation of such data. Now in its second phase, the Sea Level CCI project merges data from 9 different altimeter missions in a clear and well-documented manner, selecting the most appropriate satellite orbits and geophyiscal corrections in order to reduce the error budget. This paper summarises the corrections required, the provenance of corrections and the evaluation of options that have been adopted for the recently released v2.0 dataset (<a href="http://dx.doi.org/10.5270/esa-sea_level_cci-1993_2015-v_2.0-201612">DOI:10.5270/esa-sea_level_cci-1993_2015-v_2.0-201612</a>). This information enables scientists and other users to clearly understand which corrections have been applied and their effects on the sea level dataset. However, the overall result of these changes is that the rate of rise of global mean sea level still equates to ~3.2 mm yr<sup>−1</sup> during 1992-2015.