Though Borg rarely look alike, they share several common characteristics. Borg commonly have one eye replaced with a sophisticated ocular implant which allows them to see beyond the human visual spectrum. This implant usually projects a red laser beam, particularly in later appearances. They also usually have one arm replaced with a multi-purpose tool.

Owing to their cybernetic enhancements, all Borg are far stronger than ordinary humans to varying degrees (depending on the species the drone came from). However, they never run to their destination, and hence most species can outpace them. Borg drones are resistant to phaser fire, being completely immune to the stun setting. In addition, all Borg drones possess personal shielding which collectively adapts to phaser fire. In various episodes, phasers tend to become ineffective after a dozen shots at most, depending on the settings and time between shots. Phaser frequencies can be altered to penetrate the shield, but the Borg adapt more quickly with each modulation. Borg are also susceptible to holodeck-generated bullets (assuming the holodeck safety protocols are disengaged) and melee weapons, as demonstrated in Star Trek: First Contact.

Individual Borg rarely speak except in cases where such communication is necessary. Instead, they send a collective audio message to their targets stating that "resistance is futile", followed by a declaration that the target in question will be assimilated and its biological and technological distinctiveness will be added to their own. The exact phrasing varies among appearances, and the biological aspect is entirely absent when the Borg are first introduced.