The Tsukuba Challenge and the Nakanoshima Robot Challenge are both technical challenges in which mobile robots run autonomously in real outdoor environments. They have been held almost every year since 2007 and 2018, respectively, and many robots have participated in these public experiments. The autonomous navigation of a mobile robot in the real world, that is, not on test tracks but in environments normally used by everyday people, poses a great many challenges. The robots have to deal with environments that change with the time of day, the weather, the season, etc., and they have to deal with unexpected stationary obstacles as well as moving ones, including people, bicycles, etc. These days, demonstration tests of delivery robots are being conducted in many places, but there are still many problems that need to be solved. In this special issue, we have gathered papers detailing the insights gained from running mobile robots in the two outdoor experiments, the Tsukuba Challenge and the Nakanoshima Robot Challenge. To run a robot with a high success rate in a real environment, it is very important to devise the robot configuration, the sensor data processing, and the behavior control based on the knowledge gained from many experiences. We hope that sharing the successes and failures in the papers in this special issue will lead to further technological improvements in the future.