Do you have a bigger size?
Use this when referring to a specific item you are holding or pointing to. It means 'Do you have it in a bigger size?'.
A more general way to ask, meaning 'Is there a bigger size?'. It's very common and slightly less direct.
A statement rather than a question, meaning 'I'm looking for a bigger size'. It's a direct way to express your need.
Excuse me, this shirt is tight on me. Do you have a bigger size?
I love these shoes. Do you have them in a bigger size?
I'd like to try on this dress, but I'm looking for a bigger size.
Excuse me, is there a bigger size of these pants?
For clothing, use 'talla'. For shoes, the correct word is 'número' (e.g., '¿Tiene un número más grande?').
The word 'talla' is replaced by 'talle' (pronounced TAH-shey). You would ask, '¿Tenés un talle más grande?'. Note the use of 'vos' (tenés) instead of 'tú' (tienes).
While '¿Tiene...?' is perfectly understood, it's also very common to hear '¿Maneja una talla más grande?', where 'manejar' means 'to carry' or 'to stock'.
'Talla' is the standard term. The main difference would be the potential use of 'vosotros' for a group ('¿Tenéis...?'), but in a one-on-one exchange with a salesperson, the phrasing is identical to Latin America ('¿Tiene...?' for formal 'usted').
Using 'tamaño' instead of 'talla'. 'Tamaño' refers to general size (like a box or a portion of food), while 'talla' is specifically for clothing sizes. Asking for 'un tamaño más grande' is a common gringo mistake.
Saying 'talla grande' instead of 'talla más grande'. 'Talla grande' means 'size Large (L)'. To ask for a 'bigger size' in general, you need the comparative 'más grande'.
Using 'grande' to mean 'too big'. To say something is too big for you, the best phrase is 'Me queda grande'. Saying 'Es grande' just describes the item itself, not how it fits you.