Tener sed vs. estar sediento

The Spanish language often has different ways to express a similar idea or sentiment. That's exactly the case for the phrases 'tener sed' and 'estar sediento', both of which can be translated as 'to be thirsty'. However, they have subtle differences in use and context.

Tener sed

'Tener sed' directly translates to 'have thirst', which is equivalent to 'to be thirsty' in English. It's a commonly used phrase in everyday Spanish conversation.
Yo tengo sed después de correr un maratón.
(I am thirsty after running a marathon.)
Los niños siempre tienen sed después de jugar al fútbol.
(The children are always thirsty after playing football.)
Si tienes sed, deberías beber agua.
(If you are thirsty, you should drink water.)

Estar sediento

'Estar sediento' also translates as 'to be thirsty', however, it is less commonly used in daily conversations. It is more formal or dramatic, often seen in literature or persuasive writing.
El caminante está sediento después de viajar bajo el sol todo el día.
(The traveler is thirsty after trekking under the sun all day.)
La planta está sedienta por la falta de agua durante la sequía.
(The plant is thirsty due to the lack of water during the drought.)
¡Estoy tan sediento que podría beber un lago entero!
(I am so thirsty I could drink an entire lake!)

Summary

'Tener sed' and 'estar sediento' both express being thirsty in Spanish. While they can often be used interchangeably, 'tener sed' is more commonly used in everyday casual spoken Spanish. 'Estar sediento', on the other hand, while less commonly used in conversation, is more likely to appear in written Spanish and lends itself well to more dramatic or formal contexts.