Full-footed fins have soft, flexible foot pockets which completely surround the divers feet, including his heels. These fins are usually worn without socks or booties, but some divers like to use neoprene diving socks to prevent the fin from rubbing blisters on their feet. Full-footed fins are most commonly used in tropical or warm waters, where thermal protection is not a concern.Open-heeled fins have foot pockets that are open in the back. The foot pockets are normally made out of more rigid material than the foot pockets of full-footed fins. These fins are designed to be worn with dive booties. The sizes tend to run larger than the sizes of full-footed fins in order to accommodate the extra bulk of the booties. Because dive booties vary in thickness and shape, it is essential to try on open-heeled fins with the booties you intend to use before purchase. Open-heeled fins are used in water of all temperatures, and are essential in cold water environments for thermal protection.<b>1. Fewer Pieces of Dive Gear:</b> Diving is an equipment intensive sport, and each piece of a dive gear is essential. Because full-footed fins do not require booties, a diver has two less pieces of dive gear to remember, which makes packing for a dive trip easier and misplacing a piece of gear on a dive boat less likely.<br/><br/><b>2. Less Expensive:</b> A diver who purchases full-footed fins does not need to purchase dive booties, which typically cost anywhere from $40 to $100 USD. Divers who have already spent a significant amount of money on gear may prefer full-footed fins for the savings.<br/><br/><b>3. Less Adjustable:</b> Most open-heeled fins come with an adjustable heel strap which allows a diver to tighten or loosen the fin. In contrast, full-footed fins are not adjustable. The foot pocket either fits or it doesn&#39;t. Divers with very large or very small feet may have a difficult time finding full-footed fins that fit properly.<br/><br/><b>4. Less Protection:</b> Divers who dive primarily from boats do not have the need for foot protection. For these divers, full-footed fins may be the simplest choice. However, those who make shore entries over rough surfaces, or need to walk geared-up to the dive site may prefer open-heeled fins and dive booties for the protection. Otherwise, divers who use full-footed fins may need to wear shoes to the dive site and then leave them on the shore while diving.<br/><br/><b>5. More Difficult to Put on and Remove:</b> Properly-fitting full-footed fins are quite snug; any movement of the fins may cause blisters. Squeezing your foot into the tight pocket of a full-footed fin may be more difficult than simply loosening the strap of an open-heeled fin and then tightening it once the foot is in place.<b>1. Thermal Protection: </b>Open-heeled fins are typically used with neoprene dive booties, which help to protect a diver&#39;s feet from the cold. Full-footed fins leave a diver&#39;s feet exposed to the water. Divers who plan to make dives in cold water or who chill easily will be more comfortable in open-heeled fins with dive booties. Open-heeled fins are also essential when using a dry suit, as dry suits enclose a diver&#39;s feet. Dry suit feet can not be shoved into full-footed fins comfortably.<br/><br/><b>2. Protection From Rough Surfaces &amp; Slipping:</b> Dive booties protect a diver&#39;s feet from rough, hot, or cold surfaces, making them essential when performing shore entries over rocky ground. On a dive boat, the grip on the soles of dive booties may help a diver to keep from slipping on slick or wet surfaces.<br/><br/><b>3. Ease of Adjustment:</b> Open-heeled fins typically have adjustable straps, which make tightening or loosening the fins to fit unusual foot sizes possible. The straps can also be loosened to make donning and removing the fins easier.<br/><br/><b>4. More Expensive:</b> Purchasing open-heeled fins and dive booties usually costs more than purchasing full-footed fins. Open-heeled fins are generally more expensive than full-footed fins, and divers must account for the additional cost of the booties.<br/><br/><b>5. Booties May Cause Blisters:</b> When diving with open-heeled fins, selecting the correct dive booties is essential. Some dive booties have internal seams, which may rub uncomfortably on a diver&#39;s feet and even cause blisters. Shoes must be fit properly to avoid pinching, but dive booties must fit both the diver&#39;s feet and the fins properly. This adds an extra step to the purchasing process.Spring straps are flexible spring or bungee straps that are used in place of standard fin straps with clasps of buckles. Spring straps make donning a removing open-heeled fins incredibly easy, and often hold fins more tightly in place that standard fin straps. Spring straps may are available for most fin models.Full-footed fins work well for many warm-water diving scenarios. However, if a diver plans on making cold water dives or shore entries, or simply prefers a more adjustable fin, open-heeled fins and dive booties are the way to go. If money if not a concern, I recommend purchasing open-heeled fins, dive booties, and spring straps.