WARNING: Contains SPOILERS for Star Trek: Prodigy season 2!

Despite them being illegal under Federation law, several Star Trek ships have been fitted with a cloaking device. Star Trek‘s creator Gene Roddenberry objected to Starfleet using the cloaking technology that was utilized by their enemies, the Romulan and Klingon Empires. Star Trek: The Next Generation provided an in-universe explanation for this, in the form of the Treaty of Algeron. The Treaty was signed following the Tomed Incident, and barred Federation member worlds from developing cloaking technology. However, several Starfleet ships have defied this treaty, including an alternate reality version of the starship Enterprise.

While some Star Trek ships have broken the Treaty of Algeron with the approval of the Romulan Star Empire, others have done so in secret. One such scandal involved a young Ensign William T. Riker (Jonathan Frakes), and it was a formative moment on his journey to becoming second-in-command of the USS Enterprise-D. Centuries later, at the extreme end of the Star Trek timeline, the Treaty of Algeron no longer seems to apply, as at least one 32nd century Starfleet ship is fitted with a formerly illegal cloaking device.

6

USS Defiant

Gifted a cloaking device by the Romulan Star Empire.

The best-known Star Trek ship to possess an “illegal” cloaking device was Star Trek: Deep Space Nine‘s USS Defiant, introduced in season 3. The Romulan Star Empire provided Deep Space Nine‘s Defiant with a cloaking device in exchange for intelligence on the Gamma Quadrant and the threat posed by the Dominion. To this end, the Defiant had a Romulan crew member on its first voyage, Sub-commander T’Rul (Martha Hackett), who operated the cloaking device while investigating the Gamma Quadrant. Commanded by Benjamin Sisko (Avery Brooks), the Defiant was an exception to the Treaty of Algeron, not the rule.

As part of the agreement, the USS Defiant could only use its cloaking device in the uncharted territory of the Gamma Quadrant. Use of the Defiant’s cloak in the Alpha and Beta Quadrants was strictly forbidden, in line with the Treaty of Algeron. However, Captain Sisko violated this stipulation whenever the situation demanded it. When the USS Defiant was eventually destroyed by the Breen in Star Trek: Deep Space Nine season 7, it ended the agreement between the Federation and the Romulan Star Empire by default.

5

USS Pegasus

Conducted illegal cloaking tests for Starfleet Intelligence.

In 2358, the Oberth-class USS Pegasus was tasked with conducting cloaking device tests, in direct contravention of the Treaty of Algeron. Commanded by Captain Erik Pressman (Terry O’Quinn), the Pegasus tested an interphasic cloaking device with disastrous results. The illegal technology placed an extraordinary strain on the Pegasus, resulting in a devastating explosion in engineering. Despite this, Pressman refused to cease the test, resulting in a mutiny and the apparent destruction of the Pegasus. Riker sided with his captain, and went along with Pressman’s cover-up, blaming the explosion, not the cloak, for the loss of the Pegasus.

12 years later, Pressman, now promoted to Rear Admiral, tasked the USS Enterprise-D with recovering the USS Pegasus before its illegal cloak was discovered by the Romulans. However, the Enterprise wasn’t fast enough and found itself trapped inside an asteroid, pinned down by the Romulans. To save his crew, Riker decided to come clean about the Pegasus’ cloak, exposing Pressman’s breach of the Treaty of Algeron, and risking his own career. To escape the asteroid, Picard ordered that the interphasic cloak to be fitted aboard the Enterprise, and informed the Romulan Star Empire about the Pegasus’ treaty violation to maintain peace.

4

USS Enterprise-D (Dreadnought)

The Anti-Time Future’s Enterprise had a cloaking device.

In the future timeline from Star Trek: The Next Generation finale, “All Good Things…”, it’s revealed that the USS Enterprise-D has had a substantial refit. As well as being upgraded with heavier weapons and a third nacelle, the so-called “Dreadnought” Enterprise-D also has a cloaking device. In this timeline, the Enterprise was the personal flagship of Admiral Riker, and the Federation’s possession of cloaking technology is widely known about. So much so that Worf (Michael Dorn) chastizes Riker for not using the cloaked Enterprise to help Picard in the first place.

Star Trek: The Next Generation‘s finale never explicitly states what happened to the Treaty of Algeron on-screen, but Geordi La Forge (LeVar Burton) does provide a likely explanation. Geordi states that the Klingon Empire took over the Romulan Star Empire at an undisclosed point. This huge power shift in the Star Trek universe would have surely negated the Treaty of Algeron, allowing the Federation to begin developing cloaking technology. Given the tensions between the Federation and the Klingon home world in the anti-time future, cloaking technology would surely become a tactical necessity.

3

The Federation Holoship

It broke the Treaty of Algeron to “uphold” the Prime Directive.

The legality of the Federation Holoship’s cloaking device is never discussed in Star Trek: Insurrection, but given how shady Admiral Dougherty (Anthony Zerbe) was, it’s a good bet that it broke the Treaty of Algeron. While the cloak technically upheld the Prime Directive by not exposing Federation technology to a pre-warp planet, the Holoship had a more nefarious purpose. Dougherty was working in partnership with the Son’a to harvest the planet’s unique metaphasic radiation. Therefore, his Holoship was designed to relocate the Ba’ku people to another planet without their knowledge, using holodeck technology to create the illusion that they were still on solid ground.

Admiral Dougherty’s Holoship was placed at the bottom of a lake on the Ba’ku planet, awaiting deployment to transport the planet’s 600 inhabitants from their home. Captain Picard and Lt. Commander Data (Brent Spiner) exposed the Holoship’s presence on Ba’ku, abandoning Starfleet’s Prime Directive to reject the greed of Dougherty and the Son’a. Picard later used the Holoship against Dougherty and the Son’a, when Lt. Commander Worf recloaked the Holoship and used it to remove the command crew from the Son’a vessel, allowing Jean-Luc to take control and stop further metaphasic radiation from being collected.

2

The Infinity

Admiral Janeway’s top-secret ship has an illegal cloak.

In Star Trek: Prodigy season 2, episode 1, “Into the Breach, Part I”, Admiral Kathryn Janeway (Kate Mulgrew) unveils the Infinity, which was cloaked inside shuttlebay three aboard the USS Voyager-A. The existence of the Infinity was top-secret, and only Admiral Jellico (Ronny Cox), and Janeway’s senior staff were initially aware of its existence. While cloaking technology is illegal in the Federation, Prodigy season 2 is set in the wake of the Romulan supernova disaster, meaning that the Empire may have given Starfleet a dispensation in return for their assistance with the evacuation efforts.

The Infinity’s mission was to fly into the wormhole, retrieve Chakotay from the 25th century, and bring him back home. The use of a cloaking device made sense, as hiding the Infinity’s presence at such a crucial point in the timeline was vital. Unfortunately, Dal R’El (Brett Gray) and the Protostar crew discover the ship and, after a fight with Nova Squadron, end up hurtling through the wormhole. After Dal and the Infinity crew eventually returned to the 24th century empty-handed, Admiral Jellico ordered the destruction of the top-secret vessel, but once again, the Protostar crew had other ideas.

1

USS Discovery

Discovery’s 32nd century refit included a cloaking device.

Star Trek: Discovery season 3, episode 11, “Su’kal” revealed that the titular starship had been fitted with a cloaking device during its 32nd century refit. 800 years in the future, the Treaty of Algeron was nullified by the Vulcan and Romulan reunification. This allowed Starfleet to have their own cloaked starships, including the USS Discovery. Captain Michael Burnham (Sonequa Martin-Green) used the Discovery’s cloaking device sparingly, with it only seeing action in Discovery season 5 when the crew attempted to hide from Primach Ruhn’s Breen Dreadnought.

Prior to this, Lt. Sylvia Tilly (Mary Wiseman) tried and failed to use the USS Discovery’s cloaking device to hide from the Emerald Chain in Star Trek: Discovery season 3, episode 11, “Su’kal”. Starfleet’s sparing use of cloaking devices in Star Trek: Discovery‘s 32nd century honors Gene Roddenberry’s opinion on the technology. Even in the furthest future of Star Trek history, with free access to cloaking technology, Starfleet still “don’t sneak around“.