Jac Holmes, 24, of Bournemouth died on Monday, the Kurdish Hawar News reported.
"He loved what he was doing there, he loved being a soldier. He had the courage of his convictions," BBC reported Holmes' mother said.
Holmes, according to local media reports, was clearing a mine when he was injured by the explosive device.
His mother called him a "hero in my eyes."
As a foreign volunteer, he participated in multiple campaigns since 2015 including Manbij and this year in Tabqa and Raqqa.
Holmes served alongside the Kurdish People's Protection Units (YPG) in northern Syria. YPG is one of the main groups in the Syrian Democratic Forces (SDF) – the partnered ground forces of the US-led international coalition to defeat ISIS.
The SDF announced the "total liberation" of Raqqa on October 20. ISIS had referred to the city as its capital.
The SDF has continued a push into eastern Syria's Deir ez-Zor, most recently taking control of the Omar oil field on the shore of the Euphrates River, near Mayadin, which is under control of the Russian-backed Syrian regime.
With large areas of Syria and much of Iraq declared liberated from ISIS, Joseph Dunford, chairman of the US Joint Chiefs of Staff, reiterated the international coalition stance that the fight against the group continues.
"[W]e have to acknowledge that our work is not done. Even with the fall of Mosul and Raqqa, we're at an inflection point in the global campaign, not an end point," said Dunford on Monday.
US Defense Secretary James Mattis has said he expects ISIS to be squeezed in the Middle Euphrates River Valley – by Iraqi forces from the east and Syrian forces from the rest. He called this "ISIS' last stand."
Foreign officials have warned that as ISIS is defeated militarily, the fight against ISIS ideology will continue.
"I'm going to welcome chiefs of defense and representatives from 75 different countries to improve the effectiveness of our military network to defeat terrorism," said Dunford of this week's coalition meetings in Washington, D.C.
At its height, about 10 million people were living under ISIS rule, according to the Coalition, when the group controlled Iraq's second-largest city of Mosul, Syria's Raqqa, and many other areas.
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