Before you do your search see if you qualify for US bra size 38AA. To wear 38AA your measurement just below your bust should be between 32'5" - 34" (83-87cm) and the bust size should be between 34" -38" (87-97cm). 38AA bra size is equal to the UK 38A bras; Australia and New Zealand - 16AA; in France, Belgium and Spain it's 100A; and in the rest of Europe and Japan it's the bra size 85A.
Now when we know your exact size let's see where we can find the bra that you are after by using the online resources below.
Amazon US 38 bras in AA cup size are from well known lingerie brands such as Amoena, Anita, Lula Lu Petites and others.
HerRoom as well as 38AA bras, carries 38AAA, A and B cups. This link will take you to their home page and then you need to choose the Bra size category to find the ones available in your bra size. You can also pick from the color, the brand and the style. They also have the popular Ahh Bras for sale.
Marks and Spencer US and M&S UK caters for AA cups in 38 band size. You can find padded or non padded, wired and wireless comfort bras, whether full-cup or demis.
MaxCleavage is a great find for all women with small chest and AA and AAA cup sizes. Make sure that for your size 38AA, try their sister size bras 36A. They offer bras that can enhance your chest size up. They are very popular Alfred Eden triple boost gel bras, as well as other well known lingerie brands for women that carry small bras.
Use this search box to find your A to AAA cup bras, as well as any other Petite Lingerie items, petite clothing and more. Just enter the name of the item you are looking for (ex. petite blouse, petite raincoat etc) and click on "Go". Voila.