Every Pokémon in the game, once captured, will go into the Browser with a letter rank being given to the quality of the player's capture of that Pokémon. The ranks consist of S, A, B, and C, with S-Rank representing the most skillful capture and C-rank representing the worst capture. After capturing a Pokémon, if the player is able to capture that species again with a higher rank, the old rank in the Browser will be replaced with the better rank. To that end, it is possible for the player to acquire an "S-Rank Browser" by getting S-Ranks on all possible Pokémon.
Not all Pokémon in the game can be re-captured. Therefore, if the player misses the S rank on their first attempt to capture the Pokémon and then saves the game, they will not be able to get the S rank on that Pokémon without restarting the game. This page indicates which Pokémon have only one encounter, so the player can prepare accordingly and attempt to S-rank the Pokémon on their first try.
Upon successful capture of a Pokémon, the player will receive bonuses according to certain skills they displayed during the capture; the more bonuses a player gets, the higher their rank is. I don't have a source that indicates what bonuses are available or how they contribute to a ranking; the tips below are based on my experience playing the game. If you do have such a source, please contact me.
Some of the bonuses that contribute to capture rank include:
Except for the following 18 Pokémon, every Pokémon can be captured multiple times, although some only appear in the postgame or in the Capture Arena. Check the Browser page for the locations of all other Pokémon.
17 of the below Pokémon are Partner Pokémon. While the player can hold off on taking the Quests that reward them with Partner Pokémon until later in the game (when it is easier to get time bonuses and charged Styler bonuses), four Partner Pokémon have to be captured during the story to proceed. Therefore, the player will want to save before these captures and be prepared to reset if they cannot get an S-rank. These four captures are shown below.
Early in the game, the player's Rookie Mission is to capture one of Starly, Pachirisu, or Munchlax on Nabiki Beach in Vientown. Whichever Pokémon is captured here becomes the player's first Partner Pokémon. The two not selected can be obtained by completing Quests after finishing Mission 16: Execute Operation Brighton!.
Only one of Starly, Pachirisu, or Munchlax is captured during the story. The other two Partners are available during postgame Quests.
| Pokémon | Mission | |
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Starly | Capture on Nabiki Beach in Vientown during Rookie Mission: Soothe Pokémon on the Beach! |
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Pachirisu | Capture on Nabiki Beach in Vientown during Rookie Mission: Soothe Pokémon on the Beach! |
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Munchlax | Capture on Nabiki Beach in Vientown during Rookie Mission: Soothe Pokémon on the Beach! |
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Kricketot | Capture on Partner Farm in Chicole Village after completing Mission 4: Destroy the Strange Machines! |
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Croagunk | Capture on School Road during Mission 7: Teach at Ranger School! |
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Mime Jr. | Leave Volcano Cave after completing Mission 11: Get the Red Gem! |
The other 13 Partner Pokémon are all obtained in a Quest.
| Pokémon | Quest | Quest unlock requirement | |
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Cranidos | Please Save Cranidos | Reunite Ollie with his mom |
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Turtwig | Please Save Turtwig | Learn how to ride Doduo |
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Shieldon | Please Save Shieldon | Receive Mission 9: Support Sven at the Ruins! |
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Chimchar | Please Save Chimchar | Complete Mission 9: Support Sven at the Ruins! |
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Piplup | Please Save Piplup | Complete Mission 10: Get the Blue Gem! |
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Snover | Snover's Mysterious Presence | Complete Mission 11: Get the Red Gem! |
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Sneasel | Mischievous Sneasel | Complete Mission 14: Get the Yellow Gem! |
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Misdreavus | Misdreavus Mischief Mystery! | Complete Mission 14: Get the Yellow Gem! |
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Pachirisu | Pachirisu's Hide and Seek (only if the player did not pick Pachirisu at the beginning) |
Complete Mission 16: Execute Operation Brighton! |
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Munchlax | Things That Go Bump... (only if the player did not pick Munchlax at the beginning) |
Complete Mission 16: Execute Operation Brighton! |
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Starly | Starly Lost Its Way (only if the player did not pick Starly at the beginning) |
Complete Mission 16: Execute Operation Brighton! |
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Machop | What Happened to Machop!? | Complete Mission 16: Execute Operation Brighton! |
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Hippopotas | Who Is on Hippowdon's Nose? | Complete Mission 16: Execute Operation Brighton! |
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Gible | Pelipper's Plea | Complete Mission 16: Execute Operation Brighton! |
The 18th Pokémon that cannot be re-captured is Celebi. Celebi is only capturable during the final Quest, Wish for the Vien Forest, when it appears in Vien Forest. The player will need to save before engaging with Celebi after accepting this Quest and be prepared to reset if they do not get an S-rank.