In November 2018, Southern released a video that appeared to show an NGO worker admitting that she had coached asylum seekers on how to speak to immigration officials in order to gain refugee status. BuzzFeed News reported that a UNHCR spokesperson said: "Greece has rigorous asylum procedures in place, within a robust legal framework." In May 2019, Southern released a YouTube documentary, Borderless, about the refugee and migrant crisis. The film was temporarily taken down by YouTube.
In February 2018, Southern, along with Brittany Pettibone and Caolan Robertson, distributed flyers in the English town of Luton describing Allah as "gay", as part of a "social experiment" video.
In March 2018, Southern, Pettibone, and Identitarian activist Martin Sellner were all denied entry to the United Kingdom. Southern was also questioned under the Schedule 7 of the Terrorism Act 2000. Her denial of entry was due to her intentions during her March visit and on the same grounds as Pettibone and Sellner.
Shortly before a planned speaking tour of Australia in July 2018, Australia's Department of Home Affairs denied Lauren Southern an Electronic Travel Authority visa, saying it was "not a working visa". She intended to charge $79 for a basic ticket and up to $749 for an "intimate dinner". The Australian government allowed her to enter the country once she had the correct visa. Arriving at Brisbane airport, she was wearing an "It's OK to be white" shirt.
In July 2018, Southern applied for a travel visa to visit New Zealand for a speaking tour with Canadian podcaster and YouTuber Stefan Molyneux. Immigration Minister Iain Lees-Galloway described their views as "repugnant", but said they met immigration character requirements and cleared their entry. The pair had not secured a venue, as Auckland Council had cancelled their initial booking, citing health and safety concerns. The pair briefly cancelled and then resumed the tour over difficulties with the venue. The subsequent booking of a private venue was revoked by its owners. In retaliation, their venue was vandalised. The failure to find a venue was celebrated by around 1,000 protestors, who said the planned event had nothing to do with freedom of speech. Prime Minister Jacinda Ardern said Southern's views "are not those that are shared by this country".
In August 2018, the Mayor of Auckland Phil Goff tweeted that Council venues should not be used to "stir up ethnic or religious tensions", and that "we've got no obligation at all" to provide a venue for hate speech. For agreeing with the cancellation, an MP received threats of violence.
Southern has been cited as a proponent of white genocide conspiracy theory. In 2018, Southern produced a documentary called Farmlands which claimed that racially motivated farm attacks in South Africa may represent an impending genocide, a common talking point for white nationalists. While producing the documentary, Southern worked with Charlottesville Unite the Right rally attendee Simon Roche, a spokesperson for the racist, ethnonationalist (völkisch) Afrikaner organization Suidlanders. In 2017, Southern produced a video on the Great Replacement conspiracy theory, which posits that non-white immigration will lead to a "genocide" of white Europeans. Southern's video is credited with helping to popularize the conspiracy theory.