Redlands is about 100 kilometres east of downtown Los Angeles on Interstate 10 — typically 90 minutes by car outside rush hour, considerably longer in traffic. From Palm Springs it is 75 kilometres west on the same freeway, around an hour.
The nearest major airport is Ontario International (ONT), about 45 kilometres west and the practical choice if you can fly into it; LAX is bigger and busier but 130 kilometres away and slow to reach in traffic. San Bernardino International is closer but has very limited commercial service. Palm Springs International is another option if you are combining the desert and the mountains.
The Arrow rail service opened in 2022 and connects Redlands to San Bernardino, where you can change for the Metrolink to Los Angeles. The Arrow's three Redlands stations — Downtown, Esri, and University — make the eastern half of town accessible without a car.