Sedan (4SD)

WARNING: This page is about a different car, the 2017 Mazda 3. However, it is still accessible from the selected car via links, so may be relevant.

Lower the rear seat back.
Partially peel back the seaming welt.
Remove the fastener.

Fig 1: Removing C-Pillar Trim Fastener - Sedan (4SD)
Courtesy of MAZDA MOTORS CORP.
Move the tire house trim in the direction of the arrow shown in the figure and partially peel it back until the hooks and clip are detached.

Fig 2: Moving Tire House Trim Of C-Pillar Trim
Courtesy of MAZDA MOTORS CORP.
Pull the C-pillar trim in the direction of the arrow in the order of (1), (2) while detaching the clip A, clip B and clip C.

Fig 3: Pulling C-Pillar Trim
Courtesy of MAZDA MOTORS CORP.
Remove the C-pillar trim in the direction of the arrow in the order of (1), (2) while detaching the guide (1), guide (2), and guide (3).

Fig 4: Removing C-Pillar Trim
Courtesy of MAZDA MOTORS CORP.
Install in the reverse order of removal.