A flotilla of four boats carrying pro-Palestinian activists had been seeking to reach Gaza to highlight the Israeli blockade of the territory, with the attempt coming five years after a similar bid ended in a deadly raid.
Three of the boats were said to have turned back while a fourth, the Marianne of Gothenburg, was boarded by the Israeli navy and was being detaine to an Israeli port.
Among the passengers on the four vessels were Arab-Israeli lawmaker Basel Ghattas, Tunisia's former president Moncef Marzouki and at least one European lawmaker.
The other three ships had changed their course and were "heading back to their ports of origin," according to a statement by "Canadian Boat to Gaza," issued by the activists before the Israeli navy commandeered the Marianne.
"We once again call on the Israel to finally lift the blockade on Gaza," the statement read. "Our destination remains the conscience of humanity."
Israel imposed its blockade on Gaza in 2006 and tightened it a year later.
A number of flotillas had reached Gaza prior to May 2010, when 10 Turkish activists aboard the Mavi Marmara were killed in an Israeli raid on the six-ship flotilla.
Since then, several ships manned by pro-Palestinian activists have tried to reach the shores of Gaza, but they have all been detaine by the Israeli navy.
The latest attempt comes with the Palestinian territory yet to begin the reconstruction of thousands of homes destroyed during last summer's 50-day Israeli war on Gaza.
Fingers have been pointed at both Israel and a lack of support from international donors.