The eight teams were divided into two pools of four teams. The two pool winners took part in a play-off to determine the nation advancing to the World Group II play-offs. The four nations finishing last and second last in their pools took part in relegation play-offs, with the two losing nations being relegated to Group II for 2019.
The fourteen teams were divided into two pools of four teams and two pools of three teams. The four pool winners took part in a play-off to determine the nations advancing to the World Group II play-offs.