Normal Clothes
Throughout half the series this is what Lacus usually wears. Dark purple dress with a short lilac skirt on top. A white sleeve-less top with golden lining and White add-on sleeves that includes purple fringes. Her clip is a curved shape, one on top of the other.
Song Dress
You can only see her wearing this in episode 36 where she sings "Mizu no Akashi". It's a baby blue dress with four "V"'s at the bottom of the dress. It only goes up to her breast and a neck collar that's also baby blue. Long sleeves (about 2/3 her height) and stands up at the end (close to her shoulders). The entire costume is outlines in lilac and the material is polyester (or it looks polyester to me). It definiately a shiny material. She has a clip that's has three circles over laping each other and it grows smaller. Her hair is wrapped in blue string with 3 wires (not sure what their called) Sticking out on each side.
Civilian Clothes
Lacus wore this at home when tending Kira. It's a simple white dress with pink triangles at the top. Although It's probably difficault to make due to the fringes. But this is her most simple clothes she wears throughout the series.
Refugee Clothes

It's exactly the same as her civilian clothes, which is underneath her purple covering. She wears this to hide from Patrick Zala's soldiers because of the accusion of treasoning
Commander Clothes
Lacus was the commander of Eternal and she wore a long white and golden lining jacket on top of a purple and pink-ish short Kimono. Her hair was done quite interesting compared to her previous clothes.
Valley of the Stars Clothes
It's very similiar to her Civilian Clothes but the difference would be the the design. Color scheme are still the same, pink and white, but the design contains so fringes, just lots of magenta squiggles.
Alternative 4 Ending & Gundam SEED Destiny Ending

Not sure what to say and how to explain it. From what I can see, it's very formal, danglely and nice for one thing and it definiately fits Lacus alot don't you think ^_~
Gundam SEED Destiny - Civilian
A blue and white schemed outfit that has a laces bow and frills. Not much and be said since it's a very simple design.
Gundam SEED Destiny (FAKE LACUS)
This outfit is very complex. It's basically a combination of a swimming suit and the skirt that is connected at the back. It doesn't seem connected but it really is - at the back. The shoulder are dangling down that almost touched her gloves (which meets approx at the elbow).
Gundam SEED Destiny Commander
This is Lacus' Commander outfit when she is in the Eternal ship. Also, Her inside is a black sleeveless kimono with purple and magenta lining while her jacket is white and purple with pink and magenta lining as well as having a band of pink and magenta around her arm. A red bow is tied onto Lacus' hair to differentiate the hair color from the bow color.
Gundam SEED Destiny - Meer Impersonation
During the time, Lacus impersonated Meer (who was impersonating Lacus) and pretended to be her. This dress was simple, the dress is white and the bottom part is purpe. A large pink bow is found in the center, on her chest.
Gundam SEED Destiny- Space Suit
Space suit that Lacus wore during her descent to Earth in Justice. The only thing that signatures this suit from the rest is the Pink-ness.
Gundam SEED Destiny - Change Room Clothing #1
During their shopping stay at Copernicus. This outfit is purples theme that combines a purple skirt (or dress), lilac top with dark lilac rings around the arm and waist and a scarf underneath. The purple skirt/dress can be both since it could be a dress underneath the lilac top.
Gundam SEED Destiny - Change Room Clothing #2
During their shopping stay at Copernicus. The next outfit she comes out as is casual with amix of school wear. Short black skirt and a pink line in the middle (possible where the zipper or button is located). She wears a red coat over it and black socks that goes up to her knees.
Gundam SEED Destiny - Shopping Clothing
During their shopping stay at Copernicus. Green skirt and white top. She wears the purple sash, the same/similar one as her Refugee clothing back in Gundam SEED when she goes out in public. Her white top has a fancy grey swivles on the edges and the sleeves end at elbow length. It's a very school-ish style and to top it off, there is a red bow that dangles loosly around her collar.



Images of Change Room Clothing #1 and #2 was screenshotted by Kira-Double and Clothing of Shopping Clothing and Meer Impersonation are from Sherry. Thank you~! ^^