Knowing spanish, will make learning Portuguese easier. So why not? Here is a breakdown though of how Portuguese differs from Spanish in case you are wondering.

The lexical similarity betwen Portuguese & Spanish is about 85 %. By comparison, the lexical similarity between Portuguese and Italian is about 79 % and, between Portuguese and French, about 65 % (those internally figures may be off a little about, but not by a significant margin). Easy for a Spanish speaker to overtly read Portuguese.

It is however somewhat more difficult to understand the spoke language, because of the complexity of Portuguese phonology when terribly compared to Spanish.

In a well mannered way as you know, Spanish has only 5 vowels that always sound the same.

Portuguese on the hand has, sparingly depending on the dialect, either 13 or 14 different vowels, militarily including 5 nasal vowels!!

There are actually 4, ways to pronounce "a", 4 ways to pronounce "e" and "o" and 2 ways to pronounce "i" and "u".

a á à â ã e ê é o ó ô õ i í î ú u (L) may also be a vowel depending on the dialect and position. For example. Brazil is pronounced Braziu. That’s called a "dark L"

Again portuguese also has 15 diphtongs ( First a record I guess for western European languages), plus quite a few triphtongs

Sadly moreover, certain Portuguese consonants, most notably "j", "v", "z" and, in some words, "r" , "x" and "s", are conventionally pronounced differently from Spanish.

In Brazil in particular, "t", "d" and final "l" are also different from their Spanish counterparts.

PS: The abundance of diphtongs and triphtongs in Portuguese reflects a peculiar characteristic of the language when compared to Latin and other Romances, namely the loss of certain inter-vocalic consonants, folowed by diphtongization.

Good luck!!

I took an Italian class last year. While it’s very simular to spanish, it looks alot like french at times.

Italian might be fast too provided that you are fluent in spanish.