Missouri Pacific Lines promoted the “Texas Riviera” (Corpus Christi, Galveston, and Houston, also called the Texas Gulf Coast) as far back as the 1920s.
   
   
8 February 1910, Dallas Morning News, “Our Climates Are Greatly Maligned,” pg. 6:
Indeed, the whole of Southwest Texas is in reality the American
Riviera, so graduated in climate, scenery and environment, that the
fastidious out to be able to satisfy themselves almost perfectly in some
part of it.
 
4 February 1927, Washington Post, pg. 9 ad:
The Texas Riviera
Houston
Galveston
Corpus Christi
 
Today warm sunshine floods the Texas Riviera…Winter weahter is unknown.
(...)
Missouri Pacific Lines
 
 
30 June 1932, Galveston (TX) Daily News, pg. 9 ad:
GALVESTON
PORT AND PLAYGROUND
 
TREASURE ISLAND…One-time headquarters of Jean Lafitte…Summer and Winter Resort on the Texas Riviera.
(...)
Missouri Pacific Lines
 
 
16 December 1935, Oakland (CA) Tribune, pg. 16:
This Texas Riviera, which real estate promoters like to call “the magic valley,” takes its grapefruit seriously.
 
 
11 February 1940, Galveston (TX) Daily News, “Browsing Around the Mainland” with Sam Stringfellow, pg. 17:
Browsing Around thinks the potential resort area generally referred to as the Texas Riviera could learn something from the West coast.
 
 
29 January 1984, Chicago Tribune, “Corpus Christi is key to ‘Riviera,’” pg. P4:
A sparkling bayfront and endless beaches are what Corpus Christi, on the Texas Riviera, has to offer vacationers in a state that is generally known for its cowboys and cactus.