How to Say "by themselves" in Spanish
The Spanish word for “by themselves” is “solas” — A2 level. This is a very common word in everyday Spanish.

Examples
Las amigas estaban solas en el parque después del cierre.
The friends were alone in the park after closing time.
Ellas prefieren trabajar solas para concentrarse mejor.
They prefer to work by themselves to concentrate better.
No me gusta dejar a mis perras solas por mucho tiempo.
I don't like to leave my female dogs alone for a long time.
Gender and Number Match
Since 'solas' acts like a descriptive word (adjective), it must perfectly match the person or thing it describes. Use 'solas' only if you are talking about multiple feminine subjects (e.g., 'las mujeres,' 'ellas').
Using 'A Solas'
The phrase 'a solas' (note the 'a') means 'in private' or 'in confidence.' Example: 'Necesito hablar contigo a solas' (I need to speak with you privately).
Mixing Genders
Mistake: “Using 'solas' when referring to a mixed group or a male group: 'Los estudiantes estaban solas.'”
Correction: Use 'solos' for mixed or male groups: 'Los estudiantes estaban solos.'
Confusing Adjective/Adverb
Mistake: “Trying to use the invariable adverb 'solo' when describing people: 'Ellas estaban solo.'”
Correction: When describing the state of being alone, 'solas' (the adjective form) is required to match the subject: 'Ellas estaban solas.'
Related Translations
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