Vulcan ranks

The military forces of the Vulcan High Command maintained a rank structure roughly equivalent to that of the Starfleet. (ENT: "Broken Bow")

Fleet commander

Fleet commanders reported directly to the High Command. They oversaw and commanded fleet engagements. (ENT: "Kir'Shara")

Captain

Captain was the rank commonly held by Vulcan starship commanders and other senior officers. (ENT: "Breaking the Ice", "Stigma") In the 1950s, Vulcan ship captains wore an angular-swirl insignia mirrored on the left and right collar, and additional dark striping from other officers on their uniform. (ENT: "Carbon Creek")

By 2151, Vulcan captains wore a single rank pin on their left collar. (ENT: "Breaking the Ice")

Captain Oratt
Captain Sopek
Captain Tavek
Captain Tellus
Captain Tok
Captain Vanik
Captain Voris

The It's A Wrap! sale and auction included several sets of Vulcan captain insignia, some with the accompanying uniform. [1] [2] [3] [4] [5] [6] [7]

Sub-commander

Sub-commander was a rank subordinate to a Vulcan captain. In dealing with Starfleet, a sub-commander was considered above the rank of commander and below the rank of captain. (ENT: "Broken Bow")

Sub-Commander Muroc
Sub-Commander T'Pol

Major

Major was a rank held by senior Vulcan field agents. (ENT: "Kir'Shara")

Major Talok

Subaltern

Subaltern was a rank that existed sometime before 2375. (VOY: "Infinite Regress")

Subaltern Lorot

Sublieutenant

Sublieutenants were junior officers of the High Command. A sublieutenant manned a security post outside Administrator V'Las' office. (ENT: "Kir'Shara")

The sublieutenant in "Kir'Shara" did not wear rank insignia.

**Ranks**
	Enlisted personnel							Commissioned officers							Flag officers
Fleet:	CRM		PO		CPO		MID CDT OC	ENS	LT JG	LT	LT CMDR	CMDR	CAPT	FCAPT	CDORE	RADM	VADM	ADM	FADM
Military:	PVT AMN	CPL LCP		SGT	SSGT	MSGT 1SGT	MID CDT OC	2nd LT	1st LT	CAPT	MAJ	LT COL	COL		BRIG	MAJ GEN	LT GEN	GEN	MARSHAL
Services:	Andorian • Bajoran • Cardassian • Ferengi • Human (CSA • Third Reich • UE MACO • USA) • Jem'Hadar • Klingon • Romulan • United Earth/Federation Starfleet • Vulcan Mirror universe: Terran Empire Starfleet • Terran Empire MACO

This chart shows only general equivalencies based on the ranks used by many governments on Earth, as well as the rest of the galaxy.

Background information

The Vulcan rank system seems to have been similar to Romulan ranks, including the use of sub-commander and sublieutenant.

The ranks of commander and lieutenant have never been referenced on-screen.