Delta's two mainstream credit cards offer discounted one-time access to Delta Sky Club lounges, while its premium card offers complimentary access whenever you fly Delta.The Gold Delta SkyMiles Credit Card from American Express offers 60,000 Delta SkyMiles when you spend $2,000 in the first three months. You can also receive a $50 statement credit when you make a Delta purchase in the first three months.When you open the Platinum Delta SkyMiles Credit Card from American Express and spend $3,000 in the first three months, you'll get 75,000 SkyMiles and 5,000 Medallion Qualification Miles (MQMs). You can also receive a $100 statement credit when you make a Delta purchase in the first three months.The premium card, theDelta Reserve Credit Card from American Express, is offering 75,000 miles and 10,000 Medallion Qualification Miles after you spend $5,000 in three months.These welcome offers are only available until October 30, 2019.Like the other major US airlines, Delta has its own network of airport lounges, called Delta Sky Clubs. These provide a place to relax before a flight, and Sky Club amenities include Wi-Fi, snacks, and drinks.One of the benefits of Delta's two mainstream credit cardsthe Gold Delta SkyMiles and the Platinum Delta SkyMiles cards from American Expressis the ability to purchase discounted access to Delta's Sky Club airport lounges. And two other credit cards can get you free Delta Sky Club access when you fly Delta.Keep in mind that we're focusing on the rewards and perks that make these credit cards great options, not things like interest rates and late fees, which will far outweigh the value of any points or miles. It's important to practice financial discipline when using credit cards by paying your balances in full each month, making payments on time, and only spending what you can afford to pay back.How can you access Delta Sky Club airport lounges'You have several options for accessing Delta's Sky Club lounges. If you're traveling in Delta One or in a premium cabin on one of Delta's SkyTeam alliance partners, you're entitled to Sky Club access, and you can also purchase a Delta Sky Club membership outright for $545. You can also get Sky Club access through Delta elite status.Finally, having the right credit card can get you complimentary or reduced-price access to a Delta Sky Club. Note that you need to have a same-day Delta boarding pass in order to access one of these lounges.Delta Sky Club access with select credit cardsUntil recently, anyone could purchase one-time access to Sky Clubs for $59 at any lounge's front desk. However, these day passes were eliminated in November 2018.Discounted access with the Gold Delta and Platinum Delta cardsFortunately, single-visit passes are still available for Gold and Platinum Delta SkyMiles cardholders. If you have one of those cards, you can buy access to the Sky Club for just $29about half the price of what used to be available to anyone flying Delta. This fee will be increasing to $39 in 2020.Those discounted lounge passes are great for travelers who occasionally fly Delta, or would only use the lounge access a few times each yearfor instance, in case of delays, long connections, or a tendency to arrive for flights a bit early.Complimentary access with the Delta ReserveIf you can see yourself using the Sky Club more often, you should instead consider Delta's premium cardthe Delta Reserve Credit Card from American Expresswhich gives the cardholder complimentary access to Sky Clubs whenever they're flying Delta. That helps offset the card's $450 annual fee.The Delta Reserve card comes with a few other perks, including a domestic first-class companion certificate, and higher upgrade priority for Delta Medallion members.Read more: Delta credit cards are getting tons of new benefits in 2020, and you can earn up to 75,000 miles with elevated welcome bonuses in OctoberComplimentary Sky Club, Centurion Lounge, and Priority Pass access with the Amex PlatinumAn alternative, if you're looking for the widest lounge access you can get from a credit card, the best option is the (not Delta-branded) Platinum Card from American Express. In addition to Sky Club access whenever flying Delta, that card offers access to Priority Pass lounges, AmEx's own Centurion and International Lounges, and more. That's a network of over 1,200 lounges around the world.The Amex Platinum has a high $550 annual fee, but it's easy to get more value than thatin my first year with the card, I got over $2,000 in value. Right now, the card offers 60,000 Amex Membership Rewards points after you spend $5,000 in the first three months.Click here to learn more about the Gold Delta SkyMiles card.Click here to learn more about the Platinum Delta SkyMiles card.Click here to learn more about the Delta Reserve card.Click here to learn more about the Amex Platinum card.More credit card coverageWhat's the best airline credit card'The best cash-back credit cardsSouthwest credit card reviewBest rewards credit cardsSEE ALSO:The best current credit card offersJoin the conversation about this storyNOW WATCH: Super-Earths are real and they could be an even better place to live than Earth Click here to read full news..