The activists have been banned from Heathrow and will have to do unpaid community work.
The barrister representing four of the activists earlier said the group had acted on "deeply-held beliefs".
They were found guilty last month of aggravated trespass and entering a security-restricted area.
During the trial the court heard the protesters' actions caused "astronomical" costs and disruption.
All the defendants must carry out 120 hours unpaid work, apart from protesters Graham Thompson, Danielle Paffard and Roberto Basto, who have previous convictions and will carry out 180 hours.
A Heathrow spokesman said: "When individuals illegally enter the airport, they cause disruption to thousands of passengers going about their business and when their actions extend airside they endanger lives.
"Heathrow supports the right to peaceful protest, but we will always prioritise the safe and smooth running of our airport."
The demonstration took place last July when the defendants from the direct action group Plane Stupid cut through a fence at Heathrow Airport and chained themselves together on a runway.
They were told when they were found guilty they could expect to receive jail sentences.
Arguing against a prison sentence Kirsty Brimelow QC, speaking for four of the defendants, told Willesden Magistrates Court they believed they had been "acting in the public interest" and highlighted what she called a "hard-fought for" tradition of civil disobedience.
She said: "We have come a long way since the days of the suffragettes, since those people would have been locked up and treated appallingly."
District Judge Deborah Wright said her understanding was that "immense" costs had been caused by the protest.
Prosecutor Robert Short said prosecution costs had reached about Â£14,000.
The defendants:
Thirteen climate change protesters whose demonstration at Heathrow caused 25 flights to be cancelled have been handed six-week suspended sentences.