SUMMARYAlthough packet delay and loss are two important parameters of the Internet performance, to the best of our knowledge, the evolution of large-scale IPv6 delay and loss performance has previously not been studied. In this paper, we analyze more than 600 end-to-end IPv6 paths between about 26 testboxes of RIPE Network Coordination Centre over two years, and compare the delay and loss performance over time with their IPv4 counterparts. We present and discuss the measurement methodologies and show that IPv6 paths have a higher delay and loss than their IPv4 counterparts. The main reason for the worse performance stems from IPv6-in-IPv4 tunnels rather than from native IPv6 paths and such tunnels are still widely used today.