
In Pokémon GO, you can earn Candies by walking with your Buddy Pokémon. It is free, rewards (Candies) are great, and is a good form of exercise (the Walking, of course).
You can Walk around with a Pokémon set as your buddy on the Map. Your buddy will only appear on the Map when its hunger meter is full, and will remain on the Map until the hunger meter is fully depleted. You can earn Candies for your Buddy Pokémon when you complete a certain Walking Distance that depends on the choice of Buddy Pokémon you picked. Click on your Buddy icon at the bottom left of your screen and you can see the Walking Distance required at the bottom of the next screen.

Do you know?
If you feed your Buddy with a Poffin, the distance needed to earn Candy will be reduced!
Best Pokémon as Buddy at 1km |
PIDGEY / PIDGEOTTO / PIDGEOT

At 1km, our top pick would be Pidgey, which evolves into Pidgeotto and Pidgeot. Pidgeot is currently a top Pokémon in the Ultra League (below 2,500 CP). At 1km, it is a great bang for your buck to burn your calories and acquire Candies of a powerful Pokémon in the Ultra League. What is more, there is also a Mega evolution form for this Pokémon – Mega Pidgeot.
MAGIKARP / GYARADOS

Another top pick as your Buddy at 1km is Gyarados – the evolution form of Magikarp. Gyarados is a top-tier Pokémon in the Master League (Above 2,500 CP) and has proven to be useful for battles against the Rocket team as well as in Raids. In addition, 400 Candies are required to evolve Magikarp to Gyarados. So every player would have made Magikarp a Buddy at some point in their game to be able to evolve Magikarp into Gyarados. Lastly, there is also a Mega evolution form for this Pokémon – Mega Gyarados.
FLETCHLING / FLETCHINDER / TALONFLAME

Another Pokémon worthy of mention, is the Fire type Pokémon Talonflame. Talonflame is a strong Pokémon for use in the Ultra League (below 2,500 CP). He is another Pokémon I would add to your Ultra League team, if you have not already.
ZIGZAGOON / LINOONE / OBSTAGOON

The last Pokémon I would include in this 1km list would be Obstagoon, a Dark/Normal type Pokémon that is strong in the Ultra League (below 2,500 CP) and another Pokémon I would add to your Ultra League team.
Best Pokémon as Buddy at 3km |
Flabébé / FLOETTE / FLORGES

The first Pokémon on the 3km list is Florges – a Fairy type Pokémon and the final evolution form of Flabébé and Floette. Amongst all the Pokémon listed here in the 3km list, this Pokémon ranks highest on the Master League (above 2,500 CP). However, this Pokémon is rarely found on the map so this Pokémon may not be accessible to new players. You should definitely make this Pokémon your Buddy if you have this Pokémon in your collection.
SWINUB / PILOSWINE / MAMOSWINE

The second Pokémon on the 3km list is Mamoswine – an Ice / Ground type Pokémon and the final evolution form of Swinub and Piloswine. Mamoswine is a top tier Pokémon in the Master League (above 2,500 CP). I have found this Pokémon to be very effective in fights against the Rocket team and Raids. Swinub does not spawn regularly on the map hence is a great choice for your Buddy Pokémon.
TOGEPI / TOGETIC / TOGEKISS

The third best Pokémon on the 3km list is Togekiss – a Fairy / Flying type Pokémon and the final evolution form of Togepi and Togetic. This is a very strong Pokémon to use in the Master League (above 2,500 CP). This Pokémon rarely spawns on the map, so it is a great reason to make this Pokémon your Buddy.
BERGMITE / AVALUGG

The fourth best Pokémon on the 3km list is Avalugg – an Ice type Pokémon and the evolution form of Bergmite. Another strong Pokémon to have in your Master League team, but one that you may consider skipping if you already have Mamoswine in your team.
DRILBUR / EXCADRILL

The next best Pokémon on the 3km list is Excadrill – a Ground / Steel type Pokémon that is the evolution form of Drilbur. This Pokémon has very quick movesets and is a very strong Pokémon in the Master League (above 2,500 CP). Its first form (Drilbur) is quite commonly found spawning on the map.
POPPLIO / BRIONNE / PRIMARINA

Last but not least, Primarina is another great Pokémon in the Master League (above 2,500 CP). This is a Water / Fairy type Pokémon and you may find Popplio spawning on your map occasionally.
MACHOP / MACHOKE / MACHAMP

A worthy mention on the 3km list is Machamp – a pure Fighting type Pokémon that is useful in both the Ultra League (below 2,500 CP) and Master League (above 2,500 CP). He is weak only against Fairy type, Flying type, and Psychic type Pokémon. Machop can be quite commonly found on the map.
Charmander / Charmeleon / Charizard

Another worthy mention on the 3km list is Charizard – the Fire / Flying type Pokémon that ranks high up in the Ultra League (below 2,500 CP) and a Pokémon that players have access to early in the game. This Pokémon has not one, but two Mega evolution forms!
Gastly / Haunter / Gengar

The final worthy mention on the 3km list is Gengar – a Ghost / Poison type Pokémon that is strong in the Ultra League (below 2,500 CP) and typically spawns frequently on the map in the month of October – the Halloween festive season.
Best Pokémon as Buddy at 5km |
Dratini / Dragonair / Dragonite

The first Pokémon on this 5km list is Dragonite – a top-tier Dragon / Flying type Pokémon in the Master League (above 2,500 CP) and very strong as well in the Ultra League (below 2,500 CP). Dragonite has been my top choice to use in battles against the Rocket Team and Raids. This Pokémon had originally dropped down the rankings with the release of new top-tier Pokémon, but has recently regained its place in the top tier as developers made adjustments. Dratini can be found spawning on the map occasionally.
BELDUM / METANG / METAGROSS

The second Pokémon on this 5km list is Metagross – a very strong Steel / Psychic Pokémon in the Master League (above 2,500 CP). This Pokémon is also commonly used to defend Gyms. Beldum can be found spawning on the map occasionally.
DEINO / ZWEILOUS / HYDREIGON

The third best Pokémon on this 5km list is Hydreigon – a very strong Dark / Dragon type Pokémon in the Master League (above 2,500 CP). Deino spawns occasionally on the map, so be sure to catch it when you see it.
MUNCHLAX / SNORLAX

The next Pokémon on the 5km list is Snorlax – a very strong Normal type Pokémon in the Master League (above 2,500 CP). One of the cutest cuddly Pokémon ever, the evolved form of this Pokémon appears on the map on very rare occasions.
PHANTUMP / TREVENANT

A worthy mention on the 5km list is Trevenant – a top tier Ghost / Grass type Pokémon in the Ultra League. Phantump spawns occasionally on the map, but spawns frequently in the month of October – Halloween festival season.
EEVEE

Eevee is a great choice as a Buddy in early-game, as well as late-game, as it evolves into many useful Pokémon, including the dark-type Umbreon (who is a Top Pokémon in Great League and Ultra League) as well as fairy-type Sylveon (who is a Top-100 Master League Pokémon). Furthermore, Eevee has 8 different evolutions, which are easily accessible to early-gamers to evolve and unlock in their Pokédex by earning candies from walking. Lastly, if you have already evolved Eevee once into a particular Pokémon (e.g. Sylveon) using the “nickname trick” (which can only be used once) and you wish to evolve another Eevee into the same Pokémon (e.g. Sylveon), you will need to earn 70 Buddy hearts with the Eevee as a Buddy (i.e. your selected Eevee has to be at Great Buddy level) in order to do so. See my post for more details: Guide on Eevee evolution.
Best Pokémon as Buddy at 20km |
The Candies of all Legendary Pokémon only drop at 20km.
At this walking distance, you should pick the best choice as Buddy to make the most of your walking efforts. We list down below the Pokémon we think you should only consider as a Buddy to earn candies for every 20km walked.
MEWTWO

This Pokémon needs no introduction. Since Pokémon GO was launched, Mewtwo has been consistently ranked as one of the top Pokémon in the game. Mewtwo is a Legendary Pokémon that provides sustainable long-term value to Pokémon GO players as Mewtwo never goes out of fashion. Mewtwo is vulnerable to only Bug, Ghost and Dark moves and Mewtwo has a Max CP of 4,178. Mewtwo is a great Pokémon to use in the Master League and Raids.