I will discuss ultralight new physics as an alternative candidate to explain some of the puzzles in modern particle physics and cosmology. I will review how it could alleviate some of the fine tuning problems in the Standard Model and how it naturally predicts dark matter in the present universe. Then, I will discuss several different ways to experimentally and observationally test the existence of ultralight new physics. I will show that a wide variety of such scenarios can be tested currently and in near future, based on recent advancements on precision astrophysics (pulsar timing array, astrometry, range measurements) as well as quantum sensors (atomic clock, gravity wave detectors). I will conclude with a few future directions and challenges for ultralight new physics searches.