Doubles
2021 Croatia Open Umag
Final
Champions	Fernando Romboli David Vega Hernández
Runners-up	Tomislav Brkić Nikola Ćaćić
Score	6–3, 7–5
Events
Singles Doubles
← 2019 · Croatia Open Umag · 2022 →

Robin Haase and Philipp Oswald were the reigning champions from when the tournament was last held in 2019,^[1] but chose not to defend their title.

Fernando Romboli and David Vega Hernández won the title, defeating Tomislav Brkić and Nikola Ćaćić in the final, 6–3, 7–5.

	First round							Quarterfinals							Semifinals							Final
	1	T Brkić N Ćaćić	6	3	[10]
	WC	D Ajduković F Ninčević	4	6	[8]			1	T Brkić N Ćaćić	6	6
		R Jebavý J Veselý	7	6					R Jebavý J Veselý	2	2
		C Taberner B Zapata Miralles	5	3											1	T Brkić N Ćaćić	6	6
	4	LD Martinez A Sitak	6	61	[6]											I Sabanov M Sabanov	1	2
		I Sabanov M Sabanov	3	77	[10]				I Sabanov M Sabanov	7	6
		S Caruso G Mager	78	2	[6]				D Džumhur A Šančić	5	0
		D Džumhur A Šančić	66	6	[10]																	1	T Brkić N Ćaćić	3	5
		R Albot P Martínez	6	77																			F Romboli D Vega Hernández	6	7
		A Begemann I Zelenay	4	65					R Albot P Martínez	6	6
		M Cecchinato S Travaglia	7	6					M Cecchinato S Travaglia	4	1
	3	R Matos A Vasilevski	5	4												R Albot P Martínez	6	68	[7]
	PR	M López J Munar	5	6	[5]											F Romboli D Vega Hernández	4	710	[10]
		F Romboli D Vega Hernández	7	4	[10]				F Romboli D Vega Hernández	3	7	[16]
	WC	A Kalender M Poljičak	6	6				WC	A Kalender M Poljičak	6	5	[14]
	2	P Cuevas F Martin	3	4

• Main Draw