NEPTUNE (North-East Pacific UnderseaNetworked Experiments) will be the world's first regional cabled ocean observatory, covering most of the 200,000 km2 Juan de Fuca tectonic plate. After several years of planning, NEPTUNE Canada should complete the installation of the northern part with five observatory nodes in late 2008; the US Congress may approve 6-year installation funding for NSF's Ocean Observatories Initiative this year, resulting in the NEPTUNE US portion becoming operational in about 2013 with probably four observatory nodes. The abundant power, high bandwidth communications, and hundreds of sensors delivering data and imagery in real or near real time will revolutionize our knowledge of the ocean environment and interacting processes. With the world's oceans in a state of crisis, the development of cabled observatory technology is most timely and will offer a data archive of unparalleled importance for new discoveries. NEPTUNE Canada has secured over $85M, mainly from the Canada Foundation for Innovation and the BC Knowledge development Fund, and $17M in-kind support. Several government departments, NSERC, and CANARIE have provided other grants and contributions. The University of Victoria (UVic) leads a consortium of 12 Canadian universities, and is required both to own and operate the observatory. UVic also leads the coastal observatory, VENUS (www.uvic.ca/venus). It has established Ocean Networks Canada as a wholly owned, not-for-profit agency to manage the NEPTUNE Canada and VENUS cabled observatory projects as national facilities. Alcatel-Lucent was contracted to design, manufacture and install the NEPTUNE Canada subsea infrastructure, with a 25-year lifespan. An 800km loop of backbone cable/repeaters/branching units is being installed in fall 2007 connecting with UVic's Port Alberni shore station, with the nodes added in 2008. NEPTUNE Canada will then install the secondary cables, junction boxes and instruments in late 2008, possibly with some in 2009, followed by testing, security protocols and commissioning.Significant challenges have been faced with: securing adequate funding; the innovative design of the nodes, junction boxes and vertical profiler; the route survey over challenging topography; building in-house a Data Management and Archive System that also incorporates an observatory control system; periodic reduction in scope and aspirations; and developing collaborative relationships, including those with the Canadian and US navies, the commercial fisheries, and the First Nations. A series of science workshops during the conceptual design and construction phases, along with external reviews, helped shape a program of community experiments with many focused on the five (with a sixth currently unfunded) sites and others plate-wide in scope. The five principal research themes are: plate tectonics and earthquake dynamics; fluid fluxes in the oceanic crust and gas hydrates in the accretionary margin; ocean-climate dynamics and impact on fisheries; dynamics of the deep sea ecosystems; and engin...