The route is mainly an east–west highway along the shores of Grand Lake St. Marys, although the section between Celina and Montezuma travels in a more north-south fashion.

[1][2] The busiest point in the route according to 2016 data was east of Lake Shore Drive in Celina, where the annual average daily traffic (AADT) was 16,775 vehicles.

SR 703 turns northwest at a boat ramp to Wayne Street, and travels through a small area of farmland before intersecting US 127 at a Y-intersection.

The concurrency, also known as South Main Street, continues along the western banks of Grand Lake St. Marys, passing by a lighthouse as it enters the town of Celina.

SR 703 then travels along the northern banks of the lake, with farmland north of the road.

[2][6] The concurrency crosses a railroad,[2] and SR 364 continues southward at East Bank Road.