Many thousands of years ago, when the Elves were yet a young race, before the first cataclysm, before the Drow and the Civil War, before the development of open-sea navigation, a group of Elven Scholars and adventurous souls threw caution to the wind and set out in a primitive ship to see what lay over the horizon. They sailed into the sun and were not seen again.
Thousands of years later, as the Elves’ maps of the known world became larger and more detailed with their sleek explorer ships going further and further every year, they came across something they never expected to see: other Elves. After a few millenia the decedents of those early explorers had adapted to life on and under the sea and flourished. They welcomed relations with the nation of their ancestors, but declined to return, choosing to keep their independence.
Physical Description: Like other Elves, Sea Elves possess a graceful, fragile physique that is accentuated by their long, pointed ears. Their eyes are wide and almond-shaped, and filled with large pupils, usually in a vibrant shade of blue. They tend toward darker skin tones, and blond hair, though white, blue and green are not uncommon. Their clothing tends to be tight-fitting and light to not hinder swimming, and frequently bedecked with beautiful shells and pearls.
Society: More even than their terrestrial cousins the Sea Elves feel a bond with nature and live in harmony with the ocean, and have an inherent bond with Magic. They lack the patience of their cousins though, being children of the capricious waves, and waterproof spellbooks are expensive so they boast few Wizards, however there is a strong thread of Sorcery running through their blood.
They are masters of fine craft and work with all of the riches of the sea, but have a very limited ability to work any metals. Most of the typical uses of metal are filled my magically enhanced glass, from tools to weapons to armor.
Religion: When the traditional gods of the Elves were destroyed, the pragmatic Sea Elves followed the lead that many of their brethren had already done and chose to follow the Goddess of the Ocean and her children. Temples were respectfully rededicated, and the society adapted.
Relations: Sea Elves are more accepting of the impulsive and rash tendencies of the younger races, being children of the wild ocean themselves. They are excellent judges of character, and are less susceptible to stereotyping than other Elves, judging individuals without predisposition with regard to race.
Alignment: Sea Elves are emotional and capricious, yet value kindness and beauty. Most Sea Elves are chaotic compassionate.
Adventurers: Many elves embark on adventures out of a desire to explore the world, leaving their aquatic realm to reclaim forgotten elven magic or search out other lost kingdoms. Sea Elves are generally tougher than other Elves, and enjoy the artistic dance of combat, but there is also a strong tendency for Sorcery among their numbers.
Sea Elf Racial Traits
+2 Dexterity, +2 Charisma, –2 Wisdom: Sea Elves are quick, but impulsive, and they tend to have strong personalities.
Medium: Sea Elves are Medium creatures and have no bonuses or penalties due to their size.
Normal Speed: Sea Elves have a base speed of 30 feet.
Low-Light Vision: Sea Elves can see twice as far as humans in conditions of dim light. See Additional Rules.
Aquatic: Sea Elves receive a +5 racial bonus to Swim checks and suffer no Armor Check Penalty to swimming from wearing Light armor. They also can hold their breath for an amount of time equal to quadruple their Constitution score.
Elven Magic: Sea Elves receive a +2 racial bonus on caster level checks made to overcome spell resistance. In addition, elves receive a +2 racial bonus on Spellcraft skill checks made to identify the properties of magic items.
Keen Senses: Sea Elves receive a +2 racial bonus on Perception skill checks.
Weapon Familiarity: Sea Elves are proficient with tridents, spears, javelins and nets, and treat any weapon with the word “elven” in its name as a martial weapon.
Languages: Sea Elves begin play speaking Common and Sea Elven. Sea Elves with high Intelligence scores can choose from the following: Elven, Celestial, Draconic, Dolphin, Whale, Goblin, Mer-kin, and Sylvan.
http://paizo.com/pathfinderRPG/prd/races.html with original content added