It did.
The Soviet invasion of Manchuria, which began Aug. 9, 1945, was one of the largest and most successful offensive operations in world history. In three weeks, the Soviet Union completely overran Manchuria, and by the first week of September, it had advanced into northern Korea and Beijing.
In addition to this successful invasion, Soviet forces invaded the Kuril Islands between Kamchatka and Hokkaido, the northernmost "home" island of Japan; and the southern half of Sakhalin Island. Both areas were considered as much a part of Japan as its four largest islands.
Initial Soviet planning included an invasion of Hokkaido and the subsequent occupation of northern Honshu, the largest and most populated island. Southern Sakhalin, once occupied, was to serve as a stepping-off point for these advances. David Glantz's The Soviet Strategic Offensive in Manchuria, 1945 is the best book yet written about the Soviet operations during this period.
Marshal Vasilevsky, the theater commander, sought permission from Stalin on Aug. 18 for an assault on Hokkaido. When Stalin failed to reply after several days, Vasilevsky sent a second message on Aug. 20, saying he intended to attack on Aug. 22. This was likely premature, as pacifying Sakhalin would have taken probably another week. At midday Aug. 22, Stalin ordered the operation suspended indefinitely.
Do you mean the mainland and home islands? Several small landings in the Kuriles did happen right at the end.
It mostly comes down to lack of resources. They frankly had neither the naval infrastructure nor air support to conduct the size of amphibious landing called for. The small landings they did manage were done with minimal support afloat and basically they ran a few old destroyers ashore and hope port facilities could be captured before the landing force were all killed or starved.
And for most of the time we are talking about the USSR was involved in a much more pressing conflict closer to home and there was not much interest in what could be seen as the ultimate sideshow and resource pit.