It was Mr Iwamoto's second attempt at the voyage after his first in 2013 ended in failure when his boat hit a whale and sank. He had to be rescued by the Japanese military.
Mr Iwamoto left California, where he currently lives, on 24 February aboard his 12-metre (40 feet) yacht called the Dream Weaver.
He made the journey alongside Doug Smith, his American navigator, who he calls "Seeing Eye Doug".
After arriving at Onahama port in Iwaki on Saturday, he told Japan's Kyodo News agency: "I didn't give up and I made my dream come true. I'm the happiest person on Earth."
According to the Japan Blind Sailing Association, Mr Iwamoto is the first blind person to successfully sail across the Pacific without stopping.
"We undertake this voyage not only for personal accomplishment, but to send a message that anything is possible when people come together," Mr Iwamoto wrote on his website.
In an effort to make the crossing the second time around, Mr Iwamoto took part in triathlons to familiarise himself with swimming in the sea.
Mr Iwamoto lost his sight at the age of 16 and subsequently took up competitive sailing and running.
He has since participated in a number of sporting events including the 2012 US Disabled Sailing Championship and the 2012 San Diego Half Marathon, according to his website.
The pair made the voyage to raise money for charity and for efforts to prevent diseases that cause blindness.
An online crowdfunding campaign raised $4,300 (£3,308) in support of the journey.