Sonics Arena was a proposed multi-purpose arena to be constructed in the SoDo neighborhood of Seattle, Washington, United States. The arena would have hosted basketball, ice hockey, and concerts. The proposal called for an arena with a capacity of around 19,000 to 20,000 seats. It was part of a larger plan to return the Seattle SuperSonics franchise, …Sonics Arena was a proposed multi-purpose arena to be constructed in the SoDo neighborhood of Seattle, Washington, United States. The arena would have hosted basketball, ice hockey, and concerts. The proposal called for an arena with a capacity of around 19,000 to 20,000 seats. It was part of a larger plan to return the Seattle SuperSonics franchise, along with adding a potential National Hockey League franchise, to the city of Seattle. The proposal was rejected in favor of redeveloping KeyArena into Climate Pledge Arena.