| 2021 Biella Challenger Indoor II | |
|---|---|
| Date | 15–21 February |
| Edition | 2nd |
| Draw | 32S / 16D |
| Surface | Hard (indoor) |
| Location | Biella, Italy |
| Champions | |
| Singles | |
 Kwon Soon-woo | |
| Doubles | |
 Hugo Nys /  Tim Pütz | |
The 2021 Biella Challenger Indoor II was a professional tennis tournament played on hard courts. It was the 2nd edition of the tournament which was part of the 2021 ATP Challenger Tour. It took place in Biella, Italy between 15 and 21 February 2021.
| Country | Player | Rank1 | Seed |
|---|---|---|---|
 ESP | Alejandro Davidovich Fokina | 54 | 1 |
 USA | Sebastian Korda | 88 | 2 |
| KOR | Kwon Soon-woo | 97 | 3 |
 ITA | Andreas Seppi | 108 | 4 |
 POL | Kamil Majchrzak | 109 | 5 |
 FRA | Antoine Hoang | 119 | 6 |
| ITA | Lorenzo Musetti | 122 | 7 |
 RUS | Evgeny Donskoy | 123 | 8 |
The following players received wildcards into the singles main draw:
The following player received entry into the singles main draw as a special exempt:
The following players received entry into the singles main draw as alternates:
The following players received entry from the qualifying draw:
The following player received entry as a lucky loser:
Kwon Soon-woo def. Lorenzo Musetti 6–2, 6–3. Hugo Nys / Tim Pütz def. 
Lloyd Glasspool / 
Harri Heliövaara 7–6(7–4), 6–3.The 2015 Challenger Pulcra Lachiter Biella was a professional tennis tournament played on outdoor red clay courts. It was part of the 2015 ATP Challenger Tour. It took place in Biella, Italy between 27 July – 2 August 2015.
The 2016 Thindown Challenger Biella is a professional tennis tournament played on outdoor red clay courts. It is part of the 2016 ATP Challenger Tour. It took place in Biella, Italy between 25 and 31 July 2016.
The 2017 Thindown Challenger Biella was a professional tennis tournament played on outdoor red clay courts. It was part of the 2017 ATP Challenger Tour. It took place in Biella, Italy between 31 July – 6 August 2017.
The 2018 Thindown Challenger Biella was a professional tennis tournament played on outdoor red clay courts. It was part of the 2018 ATP Challenger Tour. It took place in Biella, Italy between 17 and 23 September 2018.
The 2019 Thindown Challenger Biella was a professional tennis tournament played on outdoor red clay courts. It was part of the 2019 ATP Challenger Tour. It took place in Biella, Italy between 16 and 22 September 2019.
The 2020 Thindown Challenger Biella was a professional tennis tournament played on outdoor red clay courts. It was part of the 2020 ATP Challenger Tour. It took place in Biella, Italy between 28 September and 4 October 2020.
The 2021 Open Quimper Bretagne II was a professional tennis tournament played on hard courts. It was the twelfth edition of the tournament which was part of the 2021 ATP Challenger Tour. It took place in Quimper, France between 1 and 7 February 2021.
The 2021 Antalya Challenger II was a professional tennis tournament played on clay courts. It was the second edition of the tournament which was part of the 2021 ATP Challenger Tour. It took place in Antalya, Turkey between 1 and 7 February 2021.
The 2021 Biella Challenger Indoor was a professional tennis tournament played on hard courts. It was the 1st edition of the tournament which was part of the 2021 ATP Challenger Tour. It took place in Biella, Italy between 8 and 14 February 2021.
The 2021 Challenger Concepción was a professional tennis tournament played on clay courts. It was the first edition of the tournament which was part of the 2021 ATP Challenger Tour. It took place in Concepción, Chile between 15 and 21 February 2021.
The 2021 Biella Challenger Indoor III was a professional tennis tournament played on hard courts. It was the 3rd edition of the tournament which was part of the 2021 ATP Challenger Tour. It took place in Biella, Italy between 8 and 14 March 2021.
The 2021 Biella Challenger Indoor IV was a professional tennis tournament played on hard courts. It was the 4th edition of the tournament which was part of the 2021 ATP Challenger Tour. It took place in Biella, Italy between 15 and 21 March 2021.
The 2021 Garden Open was a professional tennis tournament played on clay courts. It was the twelfth edition of the tournament which was part of the 2021 ATP Challenger Tour. It took place in Rome, Italy between 19 and 25 April 2021.
The 2021 Tallahassee Tennis Challenger was a professional tennis tournament played on green clay courts. It was the 21st edition of the tournament which was part of the 2021 ATP Challenger Tour. It took place in Tallahassee, Florida, United States between 19 and 25 April 2021.
The 2021 Garden Open II was a professional tennis tournament played on clay courts. It was the thirteenth edition of the tournament which was part of the 2021 ATP Challenger Tour. It took place in Rome, Italy between 26 April and 2 May 2021.
The 2021 Biella Challenger V was a professional tennis tournament played on outdoor red clay courts. It was part of the 2021 ATP Challenger Tour. It took place in Biella, Italy between 3 and 9 May 2021.
The 2021 Biella Challenger VI was a professional tennis tournament played on outdoor red clay courts. It was part of the 2021 ATP Challenger Tour. It took in Biella, Italy between 17 and 23 May 2021.
The 2021 Biella Challenger VII was a professional tennis tournament played on outdoor red clay courts. It was part of the 2021 ATP Challenger Tour. It took in Biella, Italy between 31 May and 6 June 2021.
The 2021 Columbus Challenger was a professional challenger level tennis tournament played on indoor hard courts. It was the tenth edition of the men's tournament which was part of the 2021 ATP Challenger Tour and the first edition of the women's event, that was part of 2021 WTA 125K series. It took place in Columbus, United States between 20 and 26 September 2021.
The 2021 Rio Tennis Classic was a professional tennis tournament played on hard courts. It was the second edition of the tournament which was part of the 2021 ATP Challenger Tour. It took place in Rio de Janeiro, Brazil from 13 to 19 December 2021.
