Terraria has over forty music tracks across every version of the game. Each one will play and loop endlessly while the player is in a specific biome or while certain events are taking place. Music is individual to each player, and as such its volume can be lowered or disabled entirely within the Options menu.
All the music in Terraria was composed by Scott Lloyd Shelly of Resonance Array.
In-game, it's possible to record and play these songs using the Music Box accessory.
Soundtrack
The soundtracks can be listened to and purchased from Bandcamp as three separate volumes or from Steam as a single soundtrack. The first two volumes are also included when you buy the game on GOG.com. Tracks are listed in the order they appear on the soundtrack.
Terraria Soundtrack Volume 1
Volume 1 was released on November 1, 2011.
Overworld Day
It's a cheerful, upbeat, and simple tune that's almost surely to be the first one heard by a new player. It plays during the day in the Forest only if it is not corrupted/crimson or Hallowed. It also plays on the title screen on the mobile version.
Eerie
It's slower and more sinister than most other tracks. It always plays in the Meteorite mini-biome. It will also replace the regular night music on many surface biomes while there's a Blood Moon.
This track also played within The Corruption prior to the 1.0.6 patch, the Dungeon prior to the 1.2 patch, and the Underworld prior to the 1.3.0.1 patch.
Overworld Night
It's relatively peaceful and relaxing, but its tune is a minor one. This track plays only during the night in the Forest and Hallow surface biomes, but is replaced by Eerie when there's a Blood Moon.
Title Screen
It's a serene, solemn tune and is probably the slowest track in the game. Short and hooking, it normally only plays in the main menu of the game, before entering a world; however, it can play in-game when its corresponding music box is crafted and used.
Underground
It's fast and has an almost robotic tone. It plays within the Underground layer of the world unless the alternate/cavern soundtrack is already playing, and will continue into the Cavern layer until the end of the track, after which it transitions to the alternate soundtrack. These two are by far the largest biomes in the game before hardmode is reached. At that point, this track, along with the alternate soundtrack, may become significantly more difficult to access, as the Underground Hallow and the Underground Corruption/Underground Crimson (both of which have different tracks) will quickly start spreading through the underground.
Boss 1
It's a loud, frantic tune, similar to battle music. It plays during the fight with the Eye of Cthulhu (Desktop, Mobile, and 3DS exclusively), King Slime, Eater of Worlds, Skeletron, 
Lepus, and Turkor the Ungrateful. In hardmode, it also plays during the fight with Skeletron Prime and Duke Fishron.
It also played during the Goblin Army event prior to the 1.3.0.1 update. It still does on the Old-gen console version and 
Windows Phone version.
Jungle
With an exotic, relaxed tune, it has a unique feel to it with a heavy emphasis on percussion. It plays only in the Jungle (day and night) and its underground extension, the Underground Jungle.
This track was added in the 1.0.5 patch. Before it, the Jungle used the "Overworld Day" and "Overworld Night" themes, and the Underground Jungle used the "Underground" theme.
Corruption
Its melody somewhat resembles the Overworld Day track, but altered and slowed to sound much darker and more menacing. It plays in The Corruption during both day and night, but only on the surface. Once a world has entered hardmode, the Corruption will spread aggressively and this track will also play in Deserts, Oceans and Floating Islands that have been corrupted.
This track was added in the 1.0.6 patch. Before it, the Corruption used the "Eerie" theme.
Underground Corruption
This track is a combination of The Corruption and Underground tracks. It plays within the Underground Corruption, usually only accessible once a world has entered Hardmode, although it will play if the player is deep enough underground in The Corruption.
This track was added in the 1.1 patch.
The Hallow
It has a heavenly, happy tone and makes use of instruments related to this idea, especially the harp. It plays in The Hallow, but only on the surface and during the day. Once a world has entered hardmode, the Hallow will appear and spread aggressively and this track will also play in Deserts, Oceans and even Floating Islands that have been hallowed.
This track was added in the 1.1 patch.
Boss 2
It's a very hectic, frantic tune, and gives the feel of a chase, especially at the beginning. It plays during the fight with the Wall of Flesh and The Twins, which suits them very well.
This track was added in the 1.1 patch.
Underground Hallow
This track is a combination of The Hallow and Underground tracks. It plays within the Underground Hallow and while fighting Lepus . The song is only accessible once a world has entered Hardmode.
This track was added in the 1.1 patch.
Boss 3
It's much slower and less intense than the other boss fights, giving it a more menacing and mechanical tone. It plays during the fight with The Destroyer and Brain of Cthulhu, as well as during invasions by the Frost Legion.
This track was added in the 1.1 patch.
Terraria Soundtrack Volume 2
Volume 2 was released on September 28, 2013.
Ocean
It is a tranquil theme with a somewhat slower pace than other daytime themes. It plays in the Ocean biome, but only if it hasn't been taken by the Hallow, the Corruption or the Crimson; their respective surface themes will play then.
This track was added in the 1.2 patch, and was featured as the first track in both the 1.2 and 1.3 trailer. Note that, despite having the same name and being associated with the same biome, this theme is different to that of the console version.
Eclipse
It's dark with a varying pace and, keeping with the atmosphere of the event it plays in, features an organ to give it a classic horror feel. It plays during a Solar Eclipse.
This track was added in the 1.2 patch.
Prior to the 1.2.1.2 patch, it also played during the Pumpkin Moon event, until it was given its own theme.
Rain
It gives the effect of a peaceful and calming theme, slower and less upbeat than others. It plays during rain, overriding the Overworld Day, Overworld Night, Desert, Ocean, and Hallow themes.
This track was added in the 1.2 patch.
Alternate Day
Similar to the original Overworld Day theme, it shows a cheerful, upbeat tune similar to the Overworld Day theme, but with a more complex composition. Its Music Box is named "Alt Overworld Day" in-game.
This track was added in the 1.2 patch.
Space
It's a quick and carefree theme that makes use of many airy synths, and shares some of its instruments with the Overworld Day theme. It plays when you are in Space.
This track was added in the 1.2 patch. Similar to the Ocean theme, the Space theme is different from the console version's.
Golem
It has a fast pace without being particularly dark or menacing. It plays during the fight with the Golem and the Lunatic Cultist/ Pirate Invasion. Its Music Box is named "Boss 4" on the PC version, and "Boss 5" on the Old-gen Console version.
This track was added in the 1.2 patch.
Mushrooms
It's an offbeat, exotic, and trippy piece. It plays in the Mushroom Biome, both on the surface and underground.
This track was added in the 1.2 patch.
Crimson
It's an unnerving, dark, and unsettling theme with a faster pace than that of the Corruption. Its main melody comes near the end of the track. It plays in The Crimson. In the Mobile version, it also plays in the Underground Crimson.
This track was added in the 1.2 patch.
Lihzahrd
It's a mysterious and exotic sounding theme, feeling like being in an ancient world. It plays in the Jungle Temple. Its Music Box is named "Temple" in-game.
This track was added in the 1.2 patch.
Ice
It's a relaxed, somewhat slow paced theme with a distinct, cold, and crystalline feel. It plays in the surface Snow biome. Its Music Box is named "Snow" on the PC version.
This track was added in the 1.2 patch.
Plantera
It's a unique, rock and roll, fast track with a metal tune and prominent use of electric guitars. It plays during the fight with Plantera.
The rock and roll music could be referring to rock band Pantera sounding similar to Plantera.
This track was added in the 1.2 patch.
Dungeon
It's a sinister, dark theme that makes use of xylophones, which, in some popular works (especially old cartoons), are used to represent the sounds that bones make. It plays in the dungeon.
This track was added in the 1.2 patch. Before it, the Dungeon used the Eerie theme.
Lunar Boss
It plays during the Lunar Event. Its Music Box is named "The Towers" in-game.
This track was added in the 1.3 patch.
Terraria Soundtrack Volume 3
Volume 3 was released on October 7, 2015.
Alternate Underground
It has a different, less whimsical feel than the original Underground theme. It plays within the Underground and Cavern layers of the world, alternatively with the other Underground track.
This track was added in the 1.2.2 patch.
Underground Crimson
Like the Underground Corruption and the Underground Hallow, it is a mix of the Underground and Crimson tracks. It plays in the Underground Crimson, and the Underground Corruption on the Nintendo version.
This track was added in the 1.2.4 patch. Before this, the Underground Crimson used the basic Crimson soundtrack.
Goblin Army
A unique track for Goblin Army, it plays instead of the Boss 1 theme since 1.3. It somewhat vaguely resembles the Pumpkin Moon theme. Its Music Box is named "Goblin Invasion" in-game.
This track was added in the 1.3 patch.
The Underworld
A deep and menacing track fitting for The Underworld, with an emphasis on harsh percussion. Its Music Box is named "Hell" in-game.
This track was added in the 1.3 patch. Before it, the Underworld used the Eerie theme.
On the Nintendo version, this theme replaces all instances of Eerie, being played in the Underworld, Meteorite biome, and during a Blood Moon.
Pirate Invasion
A unique track for Pirate Invasion, it somewhat resembles the Old One's Army theme with bits of classical music.
This track was added in the 1.3 patch. Before it, the Pirate Invasion used the Golem theme and still does on the Old-gen console version, Windows Phone version, and Nintendo version.
Pumpkin Moon
It has a tune reminiscent of spooky Halloween-themed music. It plays during the Pumpkin Moon event.
This track was added in the 1.2.1.2 patch. Before it, the Pumpkin Moon used the Eclipse theme.
Frost Moon
It plays during the Frost Moon event. It vaguely resembles a Christmas song but is more upbeat and uses electric guitar.
This track was added in the 1.2.2 patch.
Martian Madness
A track that plays during the Martian Madness event.
This track was added in the 1.3 patch. It was however released on YouTube on Feb 25th, 2015, as a 1.3-spoiler[1].
Lunar Towers
A duplicate of the Lunar Boss track found in Volume 2.
Moon Lord
A unique, tenseful track that plays during the Moon Lord fight, it has a fast tempo and is fitting for a final boss. Its Music Box is named "Lunar Boss" in-game.
This track was added in the 1.3 patch.
Omitted Tracks
Currently, the following tracks are missing from the official soundtrack and are unavailable for purchase, possibly due to being originally exclusive to the console edition. They may be released in the future.
Desert
It is a simple, quiet theme inspired by ancient Egyptian music as commonly portrayed in other video games and films. It plays in the Desert biome during the day, as long as it's not raining and the desert hasn't been taken over by the Hallow, Corruption or Crimson. It also plays in the Underground Desert.
This track was added in the 1.2 patch, prior to which the Overworld Day theme was used. This theme was originally exclusive to the console version and was brought over to the PC version without being altered or replaced, unlike the Ocean and Space themes.
Underground Snow
This track is currently absent from the official soundtrack. It is a calm, mysterious, and wintery theme slightly reminiscent of the Alternate Underground theme. It plays in the Underground Snow biome. It is played by the Ice Music Box on the Desktop version, and Snow on the Console and Mobile versions.
This track was added in the 1.2 patch, along with all the possible situations it plays in. This theme was originally exclusive to the console edition, where it was used in any Snow biome.
Boss 4
This track is currently absent from the official soundtrack. It is a frenetic, serious theme, which uses sounds resembling bee buzzes and wing hovering. It plays during the fight against the Queen Bee, Ocram, and the Eye of Cthulhu. It can be played using the Boss 5/ Boss 4 Music Box.
This track was added in the 1.2 patch, along with all the possible situations it plays in. This theme was originally exclusive to the console edition.
Sandstorm
This track is a tense theme that uses a synths to simulate wind (along with actual wind sounds) as well as a sitar to give a a sort of egyptian desert feeling. Some parts of "Boss 4" and Lunar Event theme can be heard.
This track was added in the 1.3.3 patch.
Old One's Army
This track is a calm, yet intense theme that reflects the play style of the event, and incorporates the main theme of Dungeon Defenders. It is a lot more orchestral than most other Terraria songs, and this is likely to reflect the crossover between Dungeon Defenders 2 and Terraria. At some points in the track, one may hear similar pieces from the Pirate Invasion, Title, and Goblin Army tracks, as well as instruments commonly found in other Terraria tracks.
This track was added in the 1.3.4 patch.
Old-gen console, Windows Phone, and 3DS soundtracks
The console soundtrack features a mix of the PC soundtrack and several additional tracks which are listed below. Although Blake Robinson was commissioned to create the music for the trailers, the in-game music was created by Scott Lloyd Shelly.
Ocean
A happy, peaceful sounding track that plays in the Ocean biome that can remind one of the waters. It is completely different from the PC version's Ocean theme.
Space
This track plays in Space. It is completely different from the Desktop version's Space theme. This track has a slower and calmer feeling, like being free.
Tutorial
This track plays during the Tutorial on the Console version, Mobile version, and 3DS versions.
Title
This track plays on the title screen. It is an extended variation of the Desktop version's title soundtrack, with more instruments and expression.
Trivia
- Underground Hallow plays while fighting Lepus.
History
- Desktop 1.3.4: Added Old One's Army track.
- Desktop 1.3.3: Added Sandstorm track.
- Desktop 1.3.0.1: Added Goblin Army, Underworld, Pirate Invasion, Martian Madness, Lunar Towers, and Moon Lord tracks.
- Desktop 1.2.4: Added Underground Crimson track.
- Desktop 1.2.2: Added Alternate Underground and Frost Moon tracks.
- Desktop 1.2.1.2: Added Pumpkin Moon track.
- Desktop 1.2: Added Ocean, Eclipse, Rain, Alternate Day, Space, Golem, Boss 4, Mushrooms, Crimson, Lihzahrd, Ice, Underground Snow, Desert, Plantera, and Dungeon tracks. (Some were originally in the console version.)
- Desktop 1.1:
- Added Underground Corruption, The Hallow, Boss 2, Underground Hallow, and Boss 3 tracks.
- Music tracks can now be recorded and played back with the Music Box accessory.
- Desktop 1.0.6: Added Corruption track.
- Desktop 1.0.5: Added Jungle track.
- Desktop-Release: Introduced Overworld Day, Eerie, Night, Title, Underground, and Boss 1 tracks.