For the big NCIS franchise crossovers, you should always watch them in the in‑universe story order (Part 1 → Part 2 → Part 3), not by air time on a single channel or by show title alphabetically.

Main NCIS crossovers and watch order

2023 three‑show NCIS event

This is the big one that most fans mean when they ask “NCIS crossover which to watch first.”

Watch in this order:

  1. NCIS – Season 20, Episode 10: “Too Many Cooks” (Part 1)
  1. NCIS: Hawaiʻi – Season 2, Episode 10: “Deep Fake” (Part 2)
  1. NCIS: Los Angeles – Season 14, Episode 10: “A Long Time Coming” (Part 3)

All three episodes are one continuous case: it starts with the retirement‑party suicide and classified files in DC, then rolls into kidnappings and CIA impostors, and finally resolves with the LA‑focused manhunt and bounties on the teams.

NCIS ↔ NCIS: Los Angeles backdoor pilot

If you’re going back to the origin of NCIS: LA, there’s an earlier mini‑crossover arc.

Watch in this order:

  1. NCIS – Season 6, Episode 22: “Legend (Part I)”
  1. NCIS – Season 6, Episode 23: “Legend (Part II)”

These are backdoor pilot episodes inside NCIS that introduce Callen, Sam, and the LA office before NCIS: Los Angeles launches.

NCIS: Los Angeles ↔ Hawaii Five‑0 crossover

This one is outside the NCIS main shows but still part of the shared universe vibe.

Watch in this order:

  1. Hawaii Five‑0 – Season 2, Episode 21: “Pa Make Loa (Touch of Death)” – Part 1
  1. NCIS: Los Angeles – Season 3, Episode 21/Season 3, ep “Touch of Death” – Part 2

The case starts in Hawaii with the virus threat and then continues in LA as the joint teams chase the bioterror suspect.

Other NCIS‑verse crossover arcs

For completeness, fans usually follow this “Part 1 then Part 2” rule anywhere the story explicitly continues into another show.

Some notable arcs (always watch the NCIS episode labeled Part 1 before the linked spin‑off episode labeled Part 2):

  • “Crescent City” (NCIS ↔ NCIS: New Orleans launch) – NCIS ep first, then NCIS: NOLA ep.
  • “Sister City” – NCIS Part 1, then NCIS: NOLA Part 2.
  • “Pandora’s Box” – NCIS Part 1, then NCIS: NOLA Part 2.

Episode titles and “Part 1 / Part 2 / Part 3” labels in guides will tell you the correct sequence, and going in story order is the best way to avoid spoilers and confusion.

Quick rule of thumb

  • If it’s a multi‑show event (like the 2023 deepfake crossover), start with the NCIS (DC) hour, then Hawaiʻi, then Los Angeles.
  • If it’s a two‑part NCIS/NCIS: NOLA or NCIS/NCIS: LA case , always watch the episode explicitly marked Part 1 (usually on NCIS) before the spin‑off’s Part 2.

Information gathered from public forums or data available on the internet and portrayed here.