A 234-unit nursing home in Elkana, 30 houses in Beit Arye and 20 in Givat Zeev got the go-ahead on Tuesday.
Retrospective permits were also issued for 179 existing homes in Ofarim.
The US said it was "deeply concerned" and warned that settlement expansion posed a "very serious and growing threat" to peace with the Palestinians.
About 570,000 Israelis live in more than 100 settlements built since Israel's 1967 occupation of the West Bank and East Jerusalem. The settlements are considered illegal under international law, though Israel disputes this.
Peace Now reported that the latest planning decision by the Israeli military-run Civil Administration in the West Bank meant 2,623 housing units at settlements had been approved so far this year. The figure includes 756 illegally-built homes that have been retrospectively "legalised".
A senior US official told the AFP news agency that settlement expansion - as well as continuing demolitions of Palestinian homes - "fundamentally undermines the prospects for a two-state solution and risks entrenching a one-state reality of perpetual occupation and conflict".
"We are particularly troubled by the policy of retroactively approving illegal outposts and unauthorised settlement units," the official said.
"These policies have effectively given the government's green light for the pervasive advancement of settlement activity in a new and potentially unlimited way."
On Tuesday, Israel reacted angrily to similar criticism of its settlement activities by the UN special co-ordinator for the Middle East peace process, Nickolay Mladenov.
"It is difficult to read in these actions a genuine intention to work towards a viable two-state solution. This appears to reinforce a policy, carried out over decades, that has enabled over half a million Israelis to settle in territory that was occupied militarily in 1967," he told the UN Security Council.
A spokesman for Israeli Prime Minister Benjamin Netanyahu accused Mr Mladenov of distorting history.
"Jews have been in Jerusalem, Judea and Samaria for thousands of years and their presence there is not an obstacle to peace," David Keyes said, using the biblical names for the West Bank.
There have been numerous rounds of peace talks between Israel and the Palestinians since the early 1990s, with the last collapsing in acrimony in 2014.

Revenue Scotland is responsible for the administration and collection of Land and Building Transaction Tax (LBTT) and Scottish Landfill Tax (SLfT).
It collected £425m through LBTT and £147m from SLfT in the year from 1 April 2015 to 31 March 2016.
The Scottish government had originally forecast revenues of £498m in 2015-16, which was later increased to £508m.
Almost all (98%) of the 115,000 tax returns were submitted through the new online Scottish Electronic Tax System, exceeding an initial target of 90%.
Revenue Scotland's operating costs for administering the collection of taxes was £4.67m - lower than the Scottish government's original £4.81m budget allocation for the organisation.
Revenue Scotland's chairman, Dr Keith Nicholson, said the agency's first year had been "hugely successful", with the online tax system having "exceeded expectations and received widespread praise".
He added: "These achievements are a clear signal to the Scottish taxpayer that Revenue Scotland is operating efficiently and effectively as Scotland's devolved tax authority."
Welcoming the figures, Finance Secretary Derek Mackay said: "The scale of the challenge of introducing the first Scottish taxes in more than 300 years should not be underestimated, and it's encouraging to see this has been done so effectively."
LBTT and SLfT  came into effect on 1 April 2015, replacing their UK equivalents (Stamp Duty Land Tax and UK Landfill Tax respectively) in Scotland.
The revenue collected is transferred to the Scottish Consolidated Fund to support the delivery of public services in Scotland.
Revenue Scotland will also collect a Scottish replacement for Air Passenger Duty when it is introduced, but will not administer the Scottish Rate of Income Tax, which will continue to be the responsibility of HMRC.
Israel has approved the construction of 285 new homes at Jewish settlements in the occupied West Bank, according to the settlement watchdog Peace Now.
[NEXT_CONCEPT]
Scotland's new tax agency has collected £572m in its first year - well above the amount that had been expected.