Michelle Monaghan wears Loewe LW40103U sunglasses in The White Lotus Season 3 (2025).

Based on the extreme shadow and light on the front of the frame, the pair does match the Loewe frame.

The oval Loewe LW40103U sunglasses worn by Michelle Monaghan have a blue frame, a gold Loewe logo on the temples and grey lenses. 

The color seems blue in the image and series. We've only been able to find this pair in a more purple / violet color, but it might look lighter in the bright sunlight.

The blue Loewe LW40103U is very hard to find. There is one pair on eBay.

The same model is available in the color Black or Tortoise at Pret A Voir.

Michelle Monaghan's character Jaclyn packed a lot of sunglasses for her trip, because she wears at least 4 different pairs at the Thai resort. Read more in this article:
Ultimate Guide to The White Lotus Season 3 sunglasses

Reference: Loewe LW 40103U Chunky Anagram