ou costa da América espanhola

ou ainda

Caribe / Costa caribenha

Olá, Ana!

Abaixo, a definição de "Spanish Main" do Oxford English Dictionary, com alguns exemplos de uso:

b. Spanish Main, the mainland of America adjacent to the Caribbean Sea, esp. that portion of the coast stretching from the Isthmus of Panama to the mouth of the Orinoco; in later use also, the sea contiguous to this, or the route traversed by the Spanish register ships. Now Hist.
1725 Sloane Jamaica II. 297 This is brought from the Spanish Main, or Continent of America.
1765 Phil. Trans. LV. 50 The portrait of a child born of negro parents upon the Spanish main.
1803 J. Burney Disc. in South Sea i. i. 7 That part of the continent, since known by the names of Terra Firma, and the Spanish Main.
1839 Longfellow Wreck Hesperus iv, Then..spake an old Sailor, Had sailed the Spanish Main.
1890 J. Corbett Drake viii. 110 Cartagena was the capital of the Spanish Main.

Boa sorte e bom trabalho!