The recycling of packaging waste is an important part of the EU circular economy package, with a political focus on raising the recycling targets for post-consumer plastic packaging waste (PPW). The recycling of PPW involves at least three steps; collection, sorting and mechanical recycling. In contrast to the first two steps, mechanical recycling is poorly documented, as it is considered a free market activity. In order to provide a complete chain description the mechanical recycling yields were determined. The recovery of mass was determined for the main plastic sorting products from both major collection systems: separate collection (SC) and mechanical recovery (MR) from municipal solid waste. This technical assessment was conducted with a laboratory set-up for a standard mechanical recycling process. This analysis showed that there is a substantial sample-to-sample variation in polymeric composition between similar feedstocks and this variation is also observed in recovered masses. Next, the mechanical recycling of polyethylene feedstocks was studied more in depth. Six PE feedstocks with a gradual increasing level of complexity (from only transparent PE bottle bodies to the complete PE sorting product according to DKR 329), were prepared and mechanical recycled with the laboratory set-up. Since the polymeric composition of both the six feedstocks and the six floating milled goods were known, the net PE recycling yield could be calculated. The net PE yields are close to 100% for such a standard recycling process. Additionally, the compositional analysis revealed that contaminants are only partially removed by the standard mechanical recycling process.