by Iona Young, BBC Scotland News
Additional reporting by Bill Heaney
Police Scotland said a 34-year-old man and 31-year-old woman were arrested at the base near Helensburgh at about 17:00 on Thursday.
The woman’s nationality is unknown, but it is understood she is not Iranian.
The Royal Navy said the suspects “unsuccessfully attempted” to enter the base, which on the landward side is surrounded by high wire security fences.
The spokesperson added: “As the matter is subject to an ongoing investigation, we will not comment further.”
It is understood that the pair did not try to force their way into the base.
They asked if they could enter but were refused permission and were arrested shortly afterwards. Police Scotland said its inquiries were ongoing.
The Faslane base is home to all the Royal Navy’s nuclear submarines.
This includes the UK’s four Vanguard-class ballistic missile submarines which carry Trident nuclear missiles.
The arrests come after the US and Israel launched wide-ranging strikes on Iran, killing the country’s supreme leader on 28 February.
Iran has responded by launching attacks on Israel and US-allied states in the Gulf.
Defence secretary John Healey said the UK was reviewing its terror threat level. It remains at “substantial” meaning an attack is “likely”.
Prime Minister Sir Keir Starmer, said the UK had “stepped up protections for British bases and personnel to their highest level.”
It was not clear whether he was referring only to bases in the Middle East and the Mediterranean or to all bases at home and abroad.
Faslane has long been the focus of anti-war protests from groups such as the Campaign for Nuclear Disarmament (CND). There is a permanent peace camp at the south gate, which has been there since 1982.
The camp began as a protest against the Thatcher government’s decision to purchase the Trident nuclear missile system, but remains nearly 40 years later.
The community, composed of residents living in caravans and temporary structures, holds regular anti-nuclear demonstrations, vigils, and direct actions against nuclear weapons.
Faslane’s Vanguard submarines are the sole platform for the UK’s nuclear weapons and are due to be replaced by the new Dreadnought-class submarines after 2030.
It is also the home of Astute-class nuclear powered but conventionally armed attack submarines.
The UK’s stock of nuclear warheads is based nearby at the Royal Naval Armaments Depot (RNAD) Coulport on nearby Loch Long.
The UK has operated continuous at-sea deterrence since 1969, with first Polaris and then Trident missiles stored on and launched from nuclear-powered submarines with the capacity to remain submerged at sea for months.