The 2025 Thionville Open was a professional tennis tournament played on hardcourts. It was the first edition of the tournament which was part of the 2025 ATP Challenger Tour. It took place in Thionville, France between 3 and 9 March 2025.

Country	Player	Rank1	Seed
CRO	Borna Ćorić	143	1
BEL	Alexander Blockx	153	2
FRA	Luca Van Assche	154	3
CAN	Liam Draxl	175	4
JPN	Yuta Shimizu	180	5
FRA	Titouan Droguet	190	6
	Alibek Kachmazov	192	7
GBR	Jan Choinski	195	8

• ¹ Rankings are as of 24 February 2025.^[1]

The following players received wildcards into the singles main draw:

• Dan Added
• Felix Balshaw
• Tom Paris

The following players received entry into the singles main draw as alternates:

• Max Hans Rehberg
• Denis Yevseyev

The following players received entry from the qualifying draw:

• Matisse Bobichon
• Florian Broska
• Philip Henning
• Jakub Paul
• Vitaliy Sachko
• Henri Squire

• Borna Ćorić def. Arthur Bouquier 6–4, 6–4.

• Jakub Paul / David Pel def. Matteo Martineau / Luca Sanchez 6–1, 6–4.