The Ocean Viking on Saturday rescued 196 migrants off Libya, the humanitarian ship's operator said.
It first picked up 57 people in an inflatable dinghy struggling in international waters off the North African country, SOS Mediterranee said.
In the afternoon, the ship's crew carried out two additional rescues in the same area, plucking 54 people from a dinghy and 64 others from a wooden vessel.
In their latest operation, they saved 21 people from a wooden vessel.
The total rescued included at least two pregnant women and 33 minors, 22 of them unaccompanied.
According to the International Organization for Migration, at least 1,146 people died at sea trying to reach Europe during the first half of 2021.
SOS Mediterranee says it has rescued more than 30,000 people since February 2016, first with the ship Aquarius, then with Ocean Viking.
SOS Mediterranee accuses European Union governments of neglecting coordinated search-and-rescue action to discourage migrants from attempting the crossing from war-torn Libya, where they are often victims of organized crime and militia violence.
Libyan authorities are also accused of forcibly returning intercepted ships to Libya, even when they are in European waters.
A U.N. Human Rights Office report in late May urged Libya and the EU to overhaul their rescue operations, saying existing policies "fail to prioritize the lives, safety and human rights" of people attempting to cross from Africa.