Pantufla vs. zapatilla

In Spanish, the words 'pantufla' and 'zapatilla' both refer to types of slippers but have different regional uses and connotations.

Pantufla

The word 'pantufla' typically refers to a type of slipper that is used indoors, often associated with comfort and relaxation.
Me pongo las pantuflas cuando llego a casa.
(I put on my slippers when I get home.)
Las pantuflas de lana son muy calentitas.
(Wool slippers are very warm.)
Usa sus pantuflas para ir al baño en las noches frías.
(She uses her slippers to go to the bathroom on cold nights.)

Zapatilla

'Zapatilla' can also refer to indoor slippers but is more commonly used in some regions to describe casual shoes or sneakers used both indoors and outdoors. Its meaning can vary significantly depending on the context and region.
Voy a comprar unas zapatillas nuevas para correr.
(I'm going to buy new sneakers for running.)
Prefiero usar zapatillas en casa porque son cómodas.
(I prefer to wear slippers at home because they are comfortable.)
En España, muchos llaman 'zapatillas' a las deportivas.
(In Spain, many people call sports shoes 'zapatillas'.)

Summary

'Pantufla' mainly signifies a type of indoor slipper associated with comfort, while 'zapatilla' can mean different types of footwear depending on the context, including both indoor slippers and outdoor casual shoes or sneakers. The specific meaning of 'zapatilla' can vary by region.