Current models for the origin and constituents of Earth are based primarily on compositions of meteorites that fell recently (within the past ~1 million years) on Earth. Here we report the discovery of a probable crater (~150x100x3 km in the original dimension), which was possibly created by the impact of a large (~10 km in diameter) asteroid on a >2.5 km-deep, oxygenated ocean-floor in Pilbara, Western Australia 3.46 billion-years (Ga) ago; that is, more than 1.2 Gyr earlier than the oldest known impact crater on Earth. This discovery was made mostly through a drone-assisted survey of the distributions of impact breccias and tsunami deposits. We have also discovered numerous micro-fragments (<1 µm to ~3 mm in sizes) of the asteroid (named here as “The Apex Asteroid”) in tsunami deposits and submarine pillow lavas that were most likely generated by the asteroid impact. The micro-fragments are mostly comprised of titanite (CaTiSiO5) and rutile (TiO2), and frequently associated with native iron (Fe), carbon (C)-rich nanocrystals (e.g., SiC, graphite), coesite (high-pressure polymorph of SiO2) and a variety of alloys, such as iron-iridium (Ir) alloys with up to ~10 wt% Ir, iron-nickel (Ni)-cobalt (Co)-, aluminum (Al)-copper (Cu)-, Al-Si-, Si-C-, Fe-C- and C-Al-Ca-Cu-Fe alloys. The Apex Asteroid was much richer in titanium (Ti), calcium (Ca) and vanadium (V), and poorer in magnesium (Mg) and Fe compared to recently-fallen meteorites. Thermochemical analyses of the asteroid minerals suggest that: (1) the parental planetary body of the Apex Asteroid condensed from a solar-gas cluster that was hotter and having higher H2/H2O and H/O ratios compared to planetary bodies for the recently-fallen meteorites; (2) it may represent a major building-block of Earth; and (3) Earth and the Moon have the same chemical and isotopic compositions, but Ti atoms in the Earth’s magma oceans partitioned into the Ti-rich core and Ti-poor mantle, while most Ti atoms in the lunar magma oceans condensed as the Ti-rich mantle.