YC Defense startups
31 Y Combinator companies in Defense, 22 of them from the last four batches. Its share of recent batches is 2.8%, up from 1% in the four batches before. About 36% are AI companies by YC’s tags.
- Signal
- Active
- Since 2025
- 28 vs 1 in 2023–24
- Acquired or public
- n/a
- Listed as inactive
- n/a
Share of each batch
Defense companies as a share of each YC batch since 2015.
Newest entrants
Too few Defense companies are five or more years old to show outcomes.
- ChemPilot.ai F26 · Discover novel defense related materials/molecules.
- Kairox Systems F26 · Autonomous drones that fly and swim
- Keres F26 · Kill the drone, keep the jet. Reusable unmanned interceptors.
Building in Defense?
Open problems and funding on Questd for world of atoms.
- Y Combinator · Requests for Startups
- Andreessen Horowitz · Big Ideas 2026
- Conviction · Plausible AI Schemes
- Bessemer Venture Partners · Roadmap Investment Thesis
Defense companies, newest first
31 companies
- ChemPilot.aiAI
Discover novel defense related materials/molecules.
Fall 2026Defense3Haifa, Haifa District, Israel - Kairox Systems
Autonomous drones that fly and swim
Fall 2026Defense3San Francisco, CA, USA - Keres
Kill the drone, keep the jet. Reusable unmanned interceptors.
Fall 2026Defense3Denver, CO, USA - Polemos IndustriesAI
AI-guided ballistic missiles, cheap enough to field in numbers that…
Fall 2026Defense3San Francisco, CA, USA - Streamline Systems
Precision navigation for UAVs operating without GPS.
Fall 2026Defense2San Francisco, CA, USA - Super Powers Mobility (SPM)
Modular battery packs for mobility/vehicles
Fall 2026Defense4Pittsburgh, PA, USA - Earendil Robotics
Drone swarm defence at a small-unit level
Summer 2026Defense7San Francisco, CA, USA - Edgerun
Military exoskeletons
Summer 2026Defense5San Francisco, CA, USA - Greypoint Industries
Building drone swarms that hunt hidden enemies.
Summer 2026Defense4San Francisco, CA, USA - GUILDAI
Making Defense Manufacturing Faster and Cheaper
Summer 2026Defense2New York City, NY, USA - Hop Aero
Rocket cargo delivery to contested environments
Summer 2026Defense6Los Angeles, CA, USA - IMPACT DronesAI
Air Defense as a Service for Civilian Infrastructure.
Summer 2026Defense2San Francisco, CA, USA - Isengard Industries IncAI
Mass-produced AI strike systems and Counter-UAS
Summer 2026Defense30San Francisco, CA, USA - Mass Magnetics
USA-made magnetics for robotics and defense.
Summer 2026Defense3Boston, MA, USA - Vernius Systems, Inc.
Mass-deployable radars for air defense
Summer 2026Defense3San Francisco, CA, USA - 9 Mothers
Counter Drone Systems. $1.6m sales. We delivered for the DoW.
Spring 2026Defense19Austin, TX, USA - AICE
Submarine drones for defense
Spring 2026Defense2Paris, Île-de-France, France - Arlo Industries
Track drones and missiles without radars - Accurate, Passive, Scalable
Spring 2026Defense3New York City, NY, USA - BayMachinesAI
AI compute for defense contractors
Spring 2026Defense7San Francisco, CA, USA - Surtr Defense Systems
The hardware-agnostic operating system for drone defense
Spring 2026Defense2San Francisco, CA, USA - DAIVIN!
Tankless Dive Gear - Breath Autonomy at Sea, Land & Space
Winter 2026Defense1San Francisco, CA, USA - Seeing SystemsAI
Modular AI-Commanded Drones for Defence
Winter 2026Defense7London, England, United Kingdom - Icarus
Stratospheric birds for defense
Fall 2025Defense50Los Angeles, CA, USA - Null Labs
End-to-end Simulation for Defense Autonomy
Fall 2025Defense2San Francisco, CA, USA
Sector is YC’s own label in its public company directory. See the methodology, every sector side by side, or browse open problems worth solving.