| Doubles | ||||
|---|---|---|---|---|
| 2021 Lošinj Open | ||||
| Final | ||||
| Champions |  Andrej Martin Tristan-Samuel Weissborn | |||
| Runners-up |  Victor Vlad Cornea Ergi Kırkın | |||
| Score | 6–1, 7–6 | |||
| Events | ||||
| ||||
| ||||
This was the first edition of the tournament.
Andrej Martin and Tristan-Samuel Weissborn won the title after defeating Victor Vlad Cornea and Ergi Kırkın 6–1, 7–6 in the final.
Seeds
Sadio Doumbia / Fabien Reboul (quarterfinals)
Antonio Šančić / 
Artem Sitak (semifinals)
Marco Bortolotti / 
Sergio Martos Gornés (first round)
James Cerretani / 
Fabian Fallert (semifinals)
Draw
Key
- Q = Qualifier
- WC = Wild card
- LL = Lucky loser
- Alt = Alternate
- SE = Special exempt
- PR = Protected ranking
- ITF = ITF entry
- JE = Junior exempt
- w/o = Walkover
- r = Retired
- d = Defaulted
- SR = Special ranking
- NG = Next Gen Accelerator Program entrant
| First round | Quarterfinals | Semifinals | Final | ||||||||||||||||||||||||
| 1 | S Doumbia F Reboul
| 7 | 6 | ||||||||||||||||||||||||
 J Forejtek FC Jianu
| 5 | 4 | 1 | S Doumbia F Reboul
| 2 | 3 | |||||||||||||||||||||
| J Barranco Cosano Á López San Martín
| 3 | 5 | A Martin T-S Weissborn
| 6 | 6 | ||||||||||||||||||||||
| A Martin T-S Weissborn
| 6 | 7 | A Martin T-S Weissborn
| 6 | 6 | ||||||||||||||||||||||
| 4 | J Cerretani F Fallert
| 3 | 7 | 4 | J Cerretani F Fallert
| 3 | 4 | ||||||||||||||||||||
 D Petrović I Sabanov
| 6 | 6 | 4 | J Cerretani F Fallert
| 7 | 6 | |||||||||||||||||||||
| WC | A Kalender M Poljičak
| 2 | 7 | WC |  A Chandrasekar VS Prashanth
| 5 | 3 | ||||||||||||||||||||
| WC | A Chandrasekar VS Prashanth
| 6 | 6 | A Martin T-S Weissborn
| 6 | 7 | |||||||||||||||||||||
 N Fatić A Šetkić
| 1 | 2 | VV Cornea E Kırkın
| 1 | 6 | ||||||||||||||||||||||
| VV Cornea E Kırkın
| 6 | 6 | VV Cornea E Kırkın
| 6 | 1 | ||||||||||||||||||||||
| G Blancaneaux A Kadhe
| 6 | 7 | G Blancaneaux A Kadhe
| 3 | 6 | ||||||||||||||||||||||
| 3 | M Bortolotti S Martos Gornés
| 2 | 5 | VV Cornea E Kırkın
| 0 | 6 | |||||||||||||||||||||
 R Haase Mats Hermans
| 6 | 6 | 2 | A Šančić A Sitak
| 6 | 0 | |||||||||||||||||||||
| WC |  Anthony Genov Eldin Nokic
| 4 | 4 | R Haase M Hermans
| 5 | 4 | |||||||||||||||||||||
N Álvarez Varona Georgii Kravchenko
| 6 | 1 | 2 | A Šančić A Sitak
| 7 | 6 | |||||||||||||||||||||
| 2 | A Šančić A Sitak
| 7 | 6 | ||||||||||||||||||||||||
References
- "Lošinj Open Becomes First ATP Tennis Tournament Held on 'Island of Vitality'". www.total-croatia-news.com.