The Syrian Observatory for Human Rights, a Britain-based group, said the coalition hit at least four areas late Friday on the southern and southeastern fronts outside Kobane, also known as Ain al-Arab.
The group said the strikes had destroyed some military materiel belonging to IS, which fired dozens of shells into the town on Friday after advancing to its outskirts.
An activist from the town, Mustafa Ebdi, also reported the strikes.
"They hit last night mostly on the eastern front," he said.
The raids followed a day of relentless bombardment of Kobane by IS forces who have surrounded the town, Syria's third largest Kurdish town.
Both Ebdi and the Observatory said IS forces had fired at least 80 shells into Kobane on Friday, as they attempted to force their way into the strategic border town.
Ebdi said Kurdish forces working with Arab rebels were able to repel an evening attack by IS jihadists, but fighting was ongoing.
The Observatory too reported heavy fighting on Saturday morning, particularly on the southwestern front, adding that IS was continuing to shell the town.
There was no immediate death toll from the fighting overnight.
But Ebdi said there was some optimism among the fighters in the town on Saturday.
"Daesh fighters were saying they would be praying Eid prayers in Kobane," he said, using the Arabic acronym for IS and referring to the Muslim Eid al-Adha festival being marked on Saturday.
"But so far they have failed to enter the town."
IS began its advance towards Kobane on September 16, hoping to seize the strategic town and cement its grip over a long stretch of the Syrian-Turkish border.
The fighting has prompted a mass exodus of residents from Kobane and the surrounding countryside, with the Observatory estimating around 300,000 people have been displaced.
Smoke rises from the Syrian town of Ain al-Arab, known as Kobane by the Kurds, as Turkish soldiers take position in the southeastern town of Suruc, Sanliurfa province, near the Mursitpinar border crossing with Syria on October 3, 2014. (AFP/Getty)
Many of those, at least 186,000 according to the Turkish government, have fled over the border into Turkey.
