The Waterline Trail is part of the extensive trail network in the city of Newcastle. It connects to the May Valley Trail, passes by Lake Boren Park and ends at Newcastle Way with connections to various other trails.
Starting from May Creek Drive the trail heads north, starting on a wide grassy lane, which is a corridor for the water line owned by Seattle Public Utilities. During this first stretch the trail crosses SE 84th Way just before tracing along the western edge of Lake Boren Park. After a little under a mile, the trail arrives at 129th Avenue Southeast.
Continue along 129th Ave, a quiet residential street, for about a third of a mile, then turn left on Southeast 73rd Place for about 100 feet. Pick up the trail on the right. After two tenths of a mile the trail arrives at Newcastle Way, which is the end of the officially named Waterline Trail, but you can continue on the other side of the road on the same trail that is only different in name.