List of in-game event Pokémon in Generation IV

This is a list of Pokémon obtainable from events found in the Generation IV Pokémon games. These specific instances of Pokémon can only be obtained once per game; however, some may also be obtained in other ways as well. In addition, some Pokémon, such as, regenerate and can be encountered on a weekly basis.

Starters
These Pokémon are found in Professor Rowan's suitcase.

Eevee
This Pokémon is obtained from Bebe in Hearthome City after obtaining the National Pokédex.

Drifloon
This Pokémon can be found at the Valley Windworks every Friday after Mars is defeated for the first time.

Happiny
A Hiker NPC in Hearthome City will give the player a Happiny Egg.

Spiritomb
This Pokémon can be found at the Hallowed Tower after placing the Odd Keystone and speaking to people in The Underground 32 times.

Riolu
Riley will give the undefined a Riolu Egg after making it through Iron Island.

Rotom
This Rotom appears in the Old Chateau at night after the player obtains the National Pokédex.

Uxie
Uxie appears in Lake Acuity after Team Galactic is defeated and the player faces Dialga or Palkia.

Mesprit
Mesprit appears in Lake Verity after Team Galactic is defeated and the player faces Dialga or Palkia. After the player talks to Mesprit, it will roam Sinnoh.

Azelf
Azelf appears in Lake Valor after Team Galactic is defeated and the player faces Dialga or Palkia.

Dialga
The player can face Dialga at the Spear Pillar after Cyrus is defeated in.

Palkia
The player can face Palkia at the Spear Pillar after Cyrus is defeated in.

Heatran
After Buck returns the Magma Stone, Heatran can be encountered at Stark Mountain.

Regigigas
If the player has a Regirock, Regice, and Registeel in their party, Regigigas can be faced at the Snowpoint Temple. The Temple is inaccessible until the player obtains the National Pokédex.

Giratina
After obtaining the National Pokédex, Giratina can be found in the last room of Turnback Cave.

Cresselia
After obtaining the National Pokédex, a sailor in Canalave City will ask the player to obtain a Lunar Wing to heal his son. The player can travel to Fullmoon Island, where a Cresselia will be waiting. After talking to Cresselia, it will roam Sinnoh and leave a Lunar Wing behind.

Darkrai
If the player has a Member Card, Darkrai can be faced at Newmoon Island. The Member Card has not been released for Pokémon Diamond and Pearl, but this Darkrai is also obtainable through glitches.

Shaymin
If the player has Oak's Letter, Shaymin can be faced at Flower Paradise. Oak's Letter has not been released for Pokémon Diamond and Pearl, but this Shaymin is still obtainable through glitches.

Arceus
If the player has an Azure Flute, Arceus can be faced at the Hall of Origin. The Azure Flute has not been released.

Starters
These Pokémon are found in Professor Rowan's suitcase.

Eevee
This Eevee is obtainable from Bebe in Hearthome City. The National Pokédex is not required.

Porygon
This Porygon is obtainable from a man in Veilstone City. His house is behind the Pokémon Center.

Legendary birds
Articuno, Zapdos, and Moltres will roam Sinnoh after the player obtains the National Pokédex and talks to Professor Oak in Eterna City.

Togepi
Cynthia gives the player a Togepi Egg after Jupiter is defeated for the first time.

Regirock
If the player has an  in the party, this Regirock will appear at the Rock Peak Ruins.

Regice
If the player has an  in the party, this Regice will appear at the Iceberg Ruins.

Registeel
If the player has an  in the party, this Registeel will appear at the Iron Ruins.

Regigigas
If the player has a Regirock, Regice, and Registeel in their party, Regigigas can be faced at the Snowpoint Temple. The Temple is inaccessible until the player obtains the National Pokédex.

Drifloon
This Pokémon can be found at the Valley Windworks every Friday after Mars is defeated for the first time.

Spiritomb
This Pokémon can be found at the Hallowed Tower after placing the Odd Keystone and speaking to people in The Underground 32 times.

Rotom
This Rotom appears in the Old Chateau at night. The National Pokédex is not required.

Riolu
Riley will give the player a Riolu Egg after making it through Iron Island.

Uxie
Uxie appears at Lake Acuity after the player makes it through the Distortion World.

Mesprit
Mesprit appears at Lake Verity after the player makes it through the Distortion World. After the player talks to it, it will roam Sinnoh.

Azelf
Azelf appears at Lake Valor after the player makes it through the Distortion World.

Dialga
Dialga appears at Spear Pillar. The cave painting in Celestic Town needs to be examined, the Elite Four must be defeated, and the Adamant Orb must be collected.

Palkia
Palkia appears at the Spear Pillar. After the player defeats the Elite Four, the cave painting in Celestic Town needs to be examined and the Lustrous Orb must be collected.

Giratina
Giratina originally appears in the Distortion World in its Origin Forme. If it is not captured, it will reappear in Turnback Cave in its Altered Forme.

Heatran
After the player foils the plans of Team Galactic at Stark Mountain, Heatran will appear inside the mountain.

Cresselia
After obtaining the National Pokédex, a sailor in Canalave City will ask the player to obtain a Lunar Wing to heal his son. The player can travel to Fullmoon Island, where a Cresselia will be waiting. After talking to Cresselia, it will roam Sinnoh and leave a Lunar Wing behind.

Darkrai
If the player has a Member Card, Darkrai can be faced at Newmoon Island.

Shaymin
If the player has Oak's Letter, Shaymin can be faced at Flower Paradise.

Arceus
If the player has an Azure Flute, Arceus can be faced at the Hall of Origin.

Johto
Professor Elm sends the undefined on an errand with a choice of, , or.

Kanto
After defeating, Professor Oak will reward the player with one of the Kanto starters.

Hoenn
After defeating Red, will ask which color stone the player would like. He would give the player for "Green",  for "Red", or  for "Blue"

Red Gyarados
This Gyarados is found at the Lake of Rage.

Lapras
This Lapras can only be found on Fridays inside Union Cave.

Electrode
After defeating Ariana at Team Rocket HQ, there are three that the player must either catch or defeat in order to stop the radio transmitter.

Eevee
This Eevee is obtained from Bill in Goldenrod City after meeting him in Ecruteak City.

Snorlax
This Snorlax is found in front of Diglett's Cave. It will attack the player when awakened with the Pokégear set to the Poké Flute station.

Articuno
This Articuno is found at the Seafoam Islands.

Zapdos
This Zapdos is found outside of the Kanto Power Plant after the Machine Part is returned.

Moltres
This Moltres is found in Mt. Silver.

Dratini
This Dratini is obtained in the Dragon's Den after the player answers the Dragon Master's quiz. If the player gives an incorrect answer to one of the quiz questions, ExtremeSpeed will be replaced with Leer.

Mewtwo
This Mewtwo is found in Cerulean Cave.

Spiky-eared Pichu
This Pichu will appear at the Ilex Forest shrine if the Pikachu-colored Pichu is the first Pokémon in the player's party.

Togepi
After the player defeats Falkner, Professor Elm's aide will give the player a Togepi Egg.

Primo's Egg
If given the right combination of words at Violet City, Primo will give the player either, , or.

Sudowoodo
This Sudowoodo is found at. It attacks the player after it is watered with the SquirtBottle.

Shuckle
This Shuckle is obtained from a man in Cianwood City. It can later be returned to him.

Tyrogue
After the player defeats Kiyo in Mt. Mortar, he will give the player a Tyrogue.

Legendary beasts
After the player encounters the Legendary beasts at the Burned Tower, Raikou and Entei will roam. However Suicune will appear in various locations throughout Johto and Kanto before settling down at.

Raikou
After the player encounters the Legendary beasts at the Burned Tower, Raikou will roam Johto.

Lugia
In, Lugia can be found in the Whirl Islands after the player obtains the Silver Wing from the Radio Tower director and defeats the Kimono Girls to obtain the. In, Lugia can be found in the Whirl Islands after the player obtains the Silver Wing from a man in Pewter City.

Ho-Oh
In, Ho-Oh can be found in the Bell Tower after the player obtains the Rainbow Wing from the Radio Tower director and defeats the Kimono Girls to obtain the Clear Bell. In, Ho-Oh can be found in the Bell Tower after the player obtains the Rainbow Wing from a man in Pewter City.

Latias
In HeartGold, Latias will roam Kanto after the player speaks to Steven Stone in Vermilion City. In SoulSilver, Latias will appear in Pewter City after the player obtains the Enigma Stone.

Latios
In SoulSilver, Latios will roam Kanto after the player speaks to Steven Stone in Vermilion City. In HeartGold, Latios will appear in Pewter City after the player obtains the Enigma Stone.

Kyogre
In HeartGold, Kyogre appears in the Embedded Tower after the player obtains the Blue Orb.

Groudon
In SoulSilver, Groudon appears in the Embedded Tower after the player obtains the Red Orb.

Rayquaza
Rayquaza appears in the Embedded Tower after the player obtains the Jade Orb. The player must show Professor Oak a Groudon and Kyogre from the Embedded Tower in order to receive the Jade Orb.

Creation trio
If the player brings an event Arceus to the Sinjoh Ruins, a level 1 Dialga, Palkia, or Giratina with its respective orb can be obtained. This only works once.

Although it is impossible to legitimately access the Hall of Origin, an Arceus caught there can also be brought to the Sinjoh Ruins to allow the player to receive a Dialga, Palkia, or Giratina. At most, it is only possible to receive two of the creation trio Pokémon, by bringing one fateful encounter Arceus and one Hall of Origin Arceus to the Sinjoh Ruins, and, for the second choice, the player will not be able to choose the same Pokémon they chose the first time.