2018 Swiss Open

The 2018 Swiss Open is the 12th Swiss Open that is scheduled to be held December 10-23.

For the women's singles, it was originally going to the last Grand Slam-level tournament to have a 32 seeding system. It would originally be replaced at the 2019 Australian Open with a 16 seeding system used prior to the 2001 Wimbledon Championships. They kept their 32 seeds for the 2019 Australian Open and beyond.

It is also known to the the farewell tournament for Cameron Mathison and Larry Birkhead.

Men's singles
The men's singles seedings are special: Dragalge and Electivire announced the men's singles seedings at the 2018 Luk Thung Cup in Bangkok, held the week after the 2018 Petit Le Mans. Also, during the week, Sao Sao Sao ended the winning streak of good singers of 17 (16 out of 17 in Flygon's case) in I Can See Your Voice Thailand.

Also, IndyCar eventually used the top 12 ATP ranked players on October 15, 2018 - the date of the seedings announcement for seedings 21-32, due to Mario Lopez's withdrawal. Instead, the Quizizz version is revamped to the Abomasnow special seedings from Vanilla Ice vs. Kim Fields and Ice-T and Coco Austin vs. Vivica A. Fox; the top 12 in the points excluding the 20 full-timers qualify.

It is the first time ever that qualification for men's singles seedings are neither the usual: ATP Rankings as of November 19, 2018 nor by IndyCar standings after Sonoma on September 17, 2018.

Because they used the October 15, 2018 rankings, notable players that failed to qualify were Karen Khachanov (No.26), Daniil Medvedev (No.21), and Milos Raonic (No.20). Had IndyCar used the November 19, 2018 rankings, Khachanov would have qualified and Dimitrov would have been unseeded, as he was ranked 9th on October 15 but 19th on November 19.
 * IndyCar points are the final points standings from Sonoma.
 * Volcarona's points are Robert Wickens' driver points.
 * Note that Jirayu La-ongmanee and Apolo Anton Ohno have the same points.
 * ATP rankings are from the announcement (October 15, 2018); and points are the points from November 19, 2018 rankings.

Women's singles
Women's singles seedings are the year-end WTA Rankings on November 5, 2018.

Men's doubles
The men's doubles seeds are determined by the ATP Rankings post-London on November 19, 2018.

Women's doubles

 * 1Based on Rankings as of November 5, 2018.

Men's singles

 * Richter Belmont
 * Simon Belmont
 * Chinawut Indracusin
 * Stan Wawrinka

Women's singles

 * 🇩🇪 Jannine Weigel

Protected ranking
These following players have entered the main draw with a protected ranking.

Men's singles

 * 🇧🇷 Pietro Fittipaldi
 * 🇪🇸 Mario Lopez
 * 🇬🇧 Andy Murray

Women's singles

 * 🇧🇾 Victoria Azarenka
 * 🇷🇺 Svetlana Kuznetsova
 * 🇺🇸 Serena Williams

Withdrawals
These following players have withdrawn because of injury or illness. For women, players must have withdrawn because of playing the $100,000 ITF Dubai tournament, held the same week.

Men's singles

 * 🇨🇦 Donald Bennie (education)
 * 🇰🇷 Chung Hyeon
 * 🇦🇷 Juan Martín Del Potro (right knee injury)
 * 🇧🇪 David Goffin (right shoulder injury)
 * 🇮🇳 Maneesh Gupta (education)
 * 🇦🇺 Nick Kyrgios (elbow injury)
 * 🇭🇺 Cameron Marshall (education)
 * 🇪🇸 Rafael Nadal (ankle injury)
 * 🇸🇮 Cameron Prosic (education)

Women's singles

 * 🇷🇴 Simona Halep (back injury) → replaced by Magda Linette
 * 🇺🇸 Madison Keys (left knee injury) → replaced by Polona Hercog
 * 🇯🇵 Naomi Osaka (left thigh injury) → replaced by Anna Karolína Schmiedlová
 * Jeļena Ostapenko → replaced by Eugenie Bouchard
 * Monica Puig (right leg injury) → replaced by Luksika Kumkhum
 * 🇵🇱 Agnieszka Radwańska (retirement from tennis) → replaced by Sara Sorribes Tormo
 * 🇷🇺 Maria Sharapova (right shoulder injury) → replaced by Ekaterina Alexandrova

Trivia

 * IndyCar used Great Britain instead of England and Scotland for the Swiss Open, for Jonathan Bald, Kyle Edmund, Andy Murray and Johanna Konta.