Efficient, scalable, bufferless, and compact III–V lasers directly grown on (001)-oriented silicon-on-insulators (SOIs) are preferred light sources in Si-photonics. In this article, we present the design and operation of III–V telecom nanolaser arrays with integrated distributed Bragg reflectors (DBRs) epitaxially grown on industry-standard (001) SOI wafers. We simulated the mirror reflectance of different guided modes under various mirror architectures, and accordingly devised nanoscale DBR gratings to support high reflectivity around 1500 nm for the doughnut-shaped ${\mathrm{TE}}_{01}$ mode. Building from InP/InGaAs nanoridges grown on SOI, we fabricated subwavelength DBR mirrors at both ends of the nanoridge laser cavities and thus demonstrated room-temperature low-threshold InP/InGaAs nanolasers with a $0.28{\mathrm{\mu m}}^2$ cross-section and a 20 μm effective cavity length. The direct growth of these bufferless nanoscale III–V light emitters on Si-photonics standard (001) SOI wafers opens future options of fully integrated Si-based nanophotonic integrated circuits in the telecom wavelength regime.