Hundreds of triathletes will be on Reston roads and trails at the Reston Relay Triathlon on Sunday.

While roads will not be closed, some lanes will be blocked, and race officials are warning drivers to be extra careful on the course.

Here is what you need to know:

The race begins Sunday, June 26, 7 a.m. at Lake Newport Pool, 11601 Lake Newport Rd.

Race participants and spectators are asked to park at North Point Village Center nearby.

After the swim portion at Lake Newport, the bike 11.2-mile course will take place on the following roads: Reston Parkway, Wiehle Avenue and Baron Cameron Avenue. See a map of the bike course on the Reston Relay Triathlon website.

The 3.-1-mile run course takes place on pathways, but there will be two north Reston intersections where runners will be crossing: North Village and Center Harbor and at Center Harbor and Wiehle Ave.

Runners are to stay on the right because the first and third miles will have two-way traffic, race officials said.

For more information, visit the Reston Relay Triathlon website.

Reston’s first relay triathlon will race through North Reston on Sunday, so watch out for bikers, runners and spectators on the roads.

The Reston Relay Triathlon is a sprint-distance event for teams of competitors. It is sponsored by Reston Association and the YMCA. Proceeds will provide scholarships to support kids programs offered by The YMCA and by Reston Association, including summer camps and classes. Registration is full.

The race begins at 7 a.m. with a 400-meter swim in Lake Newport Pool. From there, the next teammate bikes three loops of a 3.50-mile course that ends back at the pool. The third teammate then runs a 5K on paths in North Reston.

The first teams should start finishing by 8 a.m. and the awards ceremonies start at Lake Newport about 10:20 a.m.

Streets on the course will not be closed, but lanes will be blocked off with cones. Police urge motorists and participants to pay attention. If you are planning to drive somewhere early Sunday, allow time for delays.

The biking course will affect Lake Newport Road to Reston Parkway to Wiehle Avenue to Baron Cameron Avenue and Reston Parkway again. See a course map on the Reston Relay Triathlon website.

The runners  will mainly be on Reston Association paths, but police will control traffic at the intersection of North Village and Center Harbor and at Center Harbor and Wiehle as the runners come through, race officials said.

Officials ask athletes and spectators to not park at Lake Newport Pool or on nearby residential streets. The best place to park is North Point Village Shopping Center.