Riley Baker (26) died in Dunedin hospital after a car driven by Chinese national Limin Ma collided with his motorcycle on August 13, 2016, on State Highway 1 near Shag Point.
The Otago Daily Times reported last week Ms McCarthy was appealing for any of them to get in touch with her.
The 24-year-old said connecting with a recipient would help her obtain closure after the death of her partner and would be on the recipient's terms.
She said this week she had been contacted by a person both parties are "99% sure" was a recipient of one of her beloved boyfriend's organs.
"They believe they are and the details match ours."
Ms McCarthy said she had been able to connect with the recipient, learning they lived a happy and fulfilling life, while she had also been able to share with them the work of Mr Baker, a freelance photographer.
"They are based in New Zealand. They are very happy, get to go out and live life to the full.
"They love Riley's photography, which made me cry a little. I feel so much better knowing that there is a person out there.
"I was just worried none of [the organs] would take and there would be no silver lining to losing him."
She said she "wasn't ready to ask" which of Mr Baker's organs they had received.
The Otago Polytechnic student, who is pursuing a career in nursing, said she had also received two messages from people who thought they might have been recipients, but were not sure, given the timing.
"Both super lovely people who told me about how grateful they are for their donors, even if it wasn't Riley and how proud they are of me for making the effort. And becoming a nurse."
