Question

soccer is more popular than swimming. Is this sentence in superlative form?

Answer 1

Soccer is more popular than swimming.

Fíjate en lo que he subrayado, esas palabras son siempre obligatorias para formar frases en la forma comparativa (comparative form), por lo tanto, la frase está en la forma comparativa.

Esa frase en forma superlativa sería:

Soccer is the most popular sport.