SR388... This is an unnamed frontier world that has yet to be examined by the Federation...

Old Bird

This is where the trouble began...

Chief Hardy

SR388 was a planet that was visited by Samus Aran during Metroid II: Return of Samus (and its remake, Metroid: Samus Returns) and then later on in the very beginning of Metroid Fusion (the rest of the game takes place on the Biologic Space Laboratories research station, which orbited the planet at the time of the game). It is, however, mentioned numerous times in the series, including in the original Metroid's manual. An asteroid belt is shown to be in close proximity. The place where Samus finds the baby on the planet is also shown in the intro of Super Metroid and in flashback in Metroid: Other M.

Complete Map of SR388 : [3]


MSR Art Gallery 033

The surface of SR388.

The barren surface of SR388 was notable for its rough, rocky and dry terrain (possibly as a result of earthquakes), with a greenish atmosphere that was likely toxic or radioactive for humans, who required special, protective suits in order to explore the planet. Storms and hurricanes were shown to happen in SR388's surface, making its conditions even harsher for life.[1] Underneath SR388's surface was a vast maze of tunnels and lava, where most of the planet's native fauna used to live, with some of them occasionally coming to the surface in search of food.[2]

MSR Chozo Memory 03

The Chozo and their machines exploring the interiors of SR388.

Since the planet was once inhabited by the Chozo, it is safe to assume that they created much of the underground complex. The ancient Chozo's colonies filled portions of the planet's interior, and many had deteriorated into ruins. The race had long since either abandoned SR388 or were wiped out. Also, many robots and drones left by the ancient civilization were still functioning during Samus's mission on the planet, but these aggressive synthetic beings have seemingly gone rogue since then. One of them was the Diggernaut, a gigantic robot used for mining operations that also attacked any intruders. Incidentally, Chozo Statues and weaponry could be found amongst the ruins.

In Metroid II: Return of Samus, lava on SR388 blocked off many of the underground caverns and ruins. The planet was described in various sources as being unstable and prone to earthquakes. In the game, these frequent earthquakes occurred and when they did, it usually happened in conjunction with the lava level decreasing, often-times exposing new areas of the planet to be explored. These earthquakes coincided with Samus exterminating a certain amount of Metroids; it is possible these lava level lowering tremors were caused by the Queen Metroid in response to Samus's efforts.

In Metroid: Samus Returns, the lava was changed to a purple hazardous liquid which would be lowered when Metroid DNA was inserted into the Chozo Seals. One of the Chozo Memories and the Official Guide states that the seal was built in order to somehow contain the Metroids within SR388 after the Metroids started rebelling against their creators. Much more traditional Lava, as seen in Sector 1 of the BSL, is still present in superheated areas of SR388.

The entirety of Metroid II and Samus Returns took place on SR388.

Biologic Space Laboratories Research StationEdit

SR388 Explosion Starchart

A large explosion engulfed the planet, but the neighboring SR387 was not destroyed.

The Biologic Space Laboratories research station was a space station created out of an asteroid that orbited SR388 in Metroid Fusion. It was created by the Galactic Federation and was the main facility where native creatures to SR388, along with other organisms from various planets and from the Bottle Ship, were brought in and studied. The Galactic Federation took a special interest in the planet after the discovery of Metroids. After Samus had been assigned to eradicate the Metroid species, the Galactic Federation went back to SR388 to collect more samples which would lead them to the discovery of the X Parasite. Eventually, this new find brought them to the station and Samus was forced to change the Biologic Space Laboratories research station's orbit so that it impacted the planet in hopes of not only destroying the X on the station, but also on SR388.

The BSL's Sector 1 (SRX), created to be a perfect replica of SR388's environment, was secretly used by the Galactic Federation to raise Metroids through their natural life-cycle; these specimens were created using the DNA of the only surviving Metroid from the species' extermination on SR388 caused by Samus Aran.

Metroid FusionEdit

SR388. A vile planet, former home of the Metroids. After so many years, the remaining creatures on this planet still seemed to be trying to recreate a natural hierarchy, one without Metroids at the top.

—Samus Aran

The events of Metroid Fusion take place mainly on the Biologic Space Laboratories research station orbiting the planet. The introduction involves landing on the planet for a research mission and Samus contracting the X Parasite. It is noteworthy that an area of the BSL, Sector 1, is a perfect recreation of SR388's environment. At the end of the game, Samus evacuates the X infested station and crashes the complex into the planet below. SR388, the former home of the Metroids, and source of the X infestation, was subsequently destroyed in a fiery explosion.[3]

Official dataEdit

Development RoomEdit

SR388 map

Map of SR388, Metroid II instruction manual

"In the 'Metroid' manga, it describes that "The Chozo developed the Metroids in order to exterminate the X living on SR-388", but I think it was previously established that "there is a high probability that the Metroid destroyed the civilization on SR-388." I think it was the X that really destroyed SR-388."

Yoshio Sakamoto: "I think SR-388's civilization was destroyed and the Chozo left for Zebes after the Metroids were released into the wild (became feral). The Galactic Federation, not knowing the reason why the Metroids were developed, requested Samus to clean them up ("Metroid II"). The result of Samus exterminating the Metroids was that the propagation of the X could permit the SR-388 ecosystem to be destroyed ("Metroid Fusion")." [4] (Samus Returns)Edit

"This desolate landscape looks empty at first glance, but there is a dark and dangerous world waiting for you just below the surface."
A lost world
"The underground labyrinth of SR388 is filled with peril at each turn. From vicious flora to killer creatures, each step you take may be your last. As you explore the dark tunnels, you may notice the remains of an ancient civilization. Could this long-lost culture be connected to the Metroids that now infest its ruins?"
DEADLY ALIEN CREATURES — (blinking light)
"The deadly Metroids that inhabit SR388 are rapidly growing in number. Worse yet, they are evolving, becoming increasingly more powerful by the minute. This vicious species must be wiped out before they destroy the entire galaxy."
DANGER IN THE DARKNESS — (blinking light)
"Countless explorers have been lost in the twisted underground tunnels of SR388. Luckily, you will be equipped with enhanced tools to help you safely navigate the treacherous caverns."
ANCIENT ARTIFACTS — (blinking light)
"Besides the equipment you start with, there are many strange items you can find throughout SR388 to assist you."


There were a variety of creatures on SR388, the most well-known being Metroids, who were at the top of the food chain. Originally, the X Parasite was the most prolific of SR388's fauna, but when the Chozo became aware of their existence, they genetically engineered the Metroids to be a perfect predator of the X, but this plan eventually backfired when the Metroids started mutating into larger, more powerful forms that even the Chozo couldn't properly deal with.

With the extinction of Metroids in SR388 through Samus Aran though, the native X Parasite population was able to resurge into the planet, infecting all of its wildlife. In order to prevent the X from further spreading throughout the galaxy, Samus had to destroy the planet by crashing the Biologic Space Laboratories research station directly into it, leading to the extinction of the X, the last living species of the planet.

There were also several mechanical creatures the Chozo left behind still known to have functioned.

Mt hero2

Earliest known visual depiction of the planet in the Nintendo Comics System story, The Coming of a Hero.

Mfend a

Biologic Space Laboratories research station

Mfend d

Destruction of SR388.

Native Inhabitants:



Chozo Robots:

Flora and faunaEdit


Metroid II: Return of SamusEdit


Metroid: Other M

BSL soldiers

Metroid Fusion

Baby birth MOM commercial

TV Commercial :60 Spot

Note: The "Phase" names are from official walkthroughs of the game in Nintendo Power. Samus Returns uses the "Surface and "Area" names.

Surface/Phase 1Edit

The Surface area of SR388, where Samus' Gunship lands, and the first Alpha Metroid is fought.

Area 1/Phase 2Edit

Area 1 contains 4 Alpha Metroids.

Area 2/Phase 3Edit

Area 2 contains 6 Alpha Metroids, 2 Gamma Metroids and the optional miniboss Arachnus.

Area 3/Phase 4Edit

Area 3 contains 1 Alpha Metroid and 8 Gamma Metroids.

Area 4/Phase 5Edit

Area 4 contains 1 Gamma Metroid.

Area 5/Phase 6Edit

Area 5 contains 1 Alpha Metroid and 1 Gamma Metroid.

Area 6/Phase 7Edit

Area 6 contains 4 Alpha Metroids and the only 3 Zeta Metroids in the game.

Area 7/Phase 8Edit

Area 7 contains 1 Alpha Metroid and 4 Omega Metroids.

Area 8/Phase 9Edit

Area 8 is the final area of SR388, containing the Queen Metroid itself, 8 normal Metroids, and the baby, which Samus brings back to Ceres Space Colony.



Metroid II Commercial.

  • SR388 is the last of four planets to be destroyed, even if not her intention, by Samus Aran, the others being Dark Aether, Phaaze and Zebes. It and Dark Aether are also the only two planets that she deliberately destroyed.
  • As mentioned before, artificial beings created by the Chozo can be found among the latter's ruins on SR388, many of which have weapons installed on them and attack on sight. It is possible the Chozo created them to keep the native wildlife at bay or more specifically, to use against the dangerous X Parasites and X infected creatures.
  • Ever since the discovery of the Metroids and Chozo ruins on SR388, it was believed that the life-sucking organisms were responsible for the supposed annihilation of the Chozo inhabitants of the planet. However, when the existence of the X Parasites was uncovered, the initial theory had been put into doubt and the X were equally considered to be the main culprit. Samus Returns eventually confirmed it was the Metroids that killed or drove the Chozo off the planet.
  • During Metroid II and Samus Returns, SR388 seemed to have a relatively low population of wildlife. The X Parasites were seemingly responsible for this, as stated by Yoshio Sakamoto and the Metroid manga. This would also explain why, in Metroid Fusion, the BSL Station's SRX (a sector that perfectly replicates the planet) contained very few of SR388's wildlife seen in the earlier games; after the extinction of Metroids, the X undoubtedly resurfaced in large numbers and steadily reduced the fauna on the planet even further (if not completely), making Galactic Federation researchers' task of collecting varied specimens a difficult one.
  • The planet's name is pronounced differently between games. Fusion renders the last two numbers as an "88" (eighty-eight) while Other M makes them distinct digits as "8-8" (eight-eight). During the countdown sequence in Fusion, the computer voice pronounces it as "SR-three-eighty-eight".
SR388 Samus Returns

Metroid: Samus Returns

  • A Galactic Federation Ripper specimen was known as "SR-478", a planet in the Nintendo Comics System was called RX 338, and the Pirate Homeworld is also identified in unused Logbook entries as "SN-883", all with very similar names to SR388. Several GF Database files identified in scans have similar names, such as BY-550.
  • The Space Pirates appear to have at least known of SR388; a scanned tank in the Metroid Processing room in Metroid Prime 3: Corruption states a specimen from SR388 had been moved and there was a 'newly discovered strain'. However, Samus encounters no Space Pirate forces or bases during her mission there. This is more or less confirmed in Metroid: Samus Returns as Proteus Ridley attacks Samus as she is leaving SR388 in order to steal the last Metroid, showing that the Space Pirates knew that Metroids existed on the planet. The intro to the latter game also states that they deliberately timed their attack on the Research Vessel Marina to coincide with their discovery of the Metroid in order to steal it, indicating they knew about the Metroid's presence.
  • In the 2014 strategy game Planetary Annihilation, the name "SR-388" was included as one of the possible names a generated planet could have in the System Editor mode.
  • An interview with several of the staff from the original Metroid state that SR388 came from a motorcycle engine, SR400: " those days, while it was called 400cc, you didn't have any choice but 388cc, but it was written like that for the time being, and that's how it came out!" [5]

The atmospheric limit.

  • In Return of Samus, it is possible for Samus to attempt to ascend into space on the Surface via her Space Jump or Spider Ball, but she will take heavy damage. The limit is denoted by a line, above which is greyed-out space. On her return to her Gunship, the atmosphere appears much higher than it initially did, which allows Samus to climb over a cliff to reach her Gunship. The atmosphere is blocked off by clouds in Samus Returns, observable if Samus visits the Surface with the Space Jump or during the Proteus Ridley battle.


Samus Returns SR388

SR388 in Samus Returns.

  1. ^ Metroid: Samus Returns - Proteus Ridley Battle
  2. ^ Metroid: Samus Returns - Post-Credits Cutscene
  3. ^ Question 31 of the "Metroid FAQ", Metroid Zero Mission Official Site


Ad blocker interference detected!

Wikia is a free-to-use site that makes money from advertising. We have a modified experience for viewers using ad blockers

Wikia is not accessible if you’ve made further modifications. Remove the custom ad blocker rule(s) and the page will load as expected.