Netflix's 'The Diplomat' Returns for Season 4 With a Perfect 100% Rotten Tomatoes Score

Netflix's political thriller "The Diplomat" released its fourth season in full on October 15, 2026, with all eight hour-long episodes available at once, according to Netflix and whats-on-netflix.com. The season launched globally at 12 a.m. Pacific Time, 3 a.m. Eastern Time and 8 a.m. British Summer Time.

On Rotten Tomatoes, the season's Tomatometer stood at 100% based on 15 reviews as of the review aggregator's own season page, making it the highest critic score of any season in the series. CBR.com reported the score at 100% from 12 verified reviews shortly after the premiere, a figure that grew as more reviews were published. The season's audience score on Rotten Tomatoes' Popcornmeter was 86%.

What the season is about

According to a plot summary reported by The Week, season 4 centers on a crisis threatening relations between the United States and the United Kingdom. The season follows a secret plan involving President Grace Penn and newly appointed Vice President Hal Wyler to steal a powerful Russian nuclear weapon, while Ambassador Kate Wyler partners with First Gentleman Todd Penn to try to stop the operation from destabilizing global security.

Filming expanded across the Atlantic, using historic properties and government landmarks around Westminster and Greenwich in London as well as locations in Washington, D.C., and New York for scenes set at the White House and other executive offices, The Week reported.

Cast changes

Keri Russell returns as Kate Wyler and Rufus Sewell as Hal Wyler, according to The Week and whats-on-netflix.com. David Gyasi, Ali Ahn, Rory Kinnear and Ato Essandoh reprise supporting roles. Allison Janney, as President Grace Penn, and Bradley Whitford, as First Gentleman Todd Penn, have been elevated to series regulars after recurring in earlier seasons. The Week reported that Celia Imrie and Michael McKean do not return this season following their characters' deaths in the story.

Critical reaction

Reviews compiled by CBR.com generally praised the season's writing and performances. Critics writing for outlets including Decider, Collider and The Playlist said the season was sharper than previous installments, pushed the show's characters further, and maintained the quality that has defined the series.

Several outlets, including whats-on-netflix.com, noted the season arrived after Allison Janney won the Emmy for Outstanding Supporting Actress in a Drama Series at the 2026 Primetime Emmy Awards — described by whats-on-netflix.com as the series' first Emmy win.

How the score compares across seasons

Despite the rising critic scores, opening-week viewership has declined with each season, according to whats-on-netflix.com, which cited figures of 8.5 million views for season one's opening week, 5.6 million for season two and 4.8 million for season three. The outlet reported the series has accumulated 783.8 million hours viewed globally since its 2023 debut.

Background

"The Diplomat," created by Debora Cahn, follows career diplomat Kate Wyler as she navigates her role as U.S. ambassador to the United Kingdom amid international crises and a turbulent marriage, according to Rotten Tomatoes' official season page. The show debuted on Netflix in 2023 and has aired annually in October for its last two seasons, per whats-on-netflix.com and CBR.com.