Enlarge State Department via Gannett News Service The government will soon release passport cards that fit in a wallet and cost half the price of a new passport. They can be used for re-entering the U.S. by land or sea from Mexico, Canada and the Caribbean only, and they are not valid for air travel. PASSPORT CARDS PASSPORT CARDS The U.S. State Department has begun producing new passport cards to be used by residents who re-enter the U.S. by land or sea from Mexico, Canada and the Caribbean. Here's a rundown on how and where to get them. Cost: $45 for adults; $35 for minors; $20 for all passport holders. Process time: About four weeks. Renewal time: 10 years for adults, five years for those under 18. Where to get them: There are 9,300 places nationwide, which you can search by ZIP code at iafdb.travel.state.gov. For more information: Go to travel.state.gov/passport. People who chafe at the cost of a passport or worry about carrying one to the beach soon will have a cheaper, easier option. The government is on the cusp of releasing passport cards that fit in a wallet and cost half the price of a new passport. About 350,000 Americans have applied for the new card, the latest step toward ratcheting up border security. People who apply now can expect a four-week wait for cards after the government mails them out to earlier applicants. The U.S. State Department expects the number of applicants to swell to 4 million by June 1, 2009. That's when U.S. travelers cannot re-enter the country from Mexico, Canada or the Caribbean without a passport, a new passport card or an equivalent document. Starting in January, travelers could no longer re-enter the country from Mexico or Canada by verbally declaring their U.S. citizenship. They must carry valid travel and identification documents, but a grace period remains in effect until next summer. The changes stem from the Western Hemisphere Travel Initiative, one of a string of post-Sept. 11 security requirements. Gradually, the government has tightened travel ID procedures in an effort to better track who enters and leaves the country. Ultimately, many millions of passport cards should be in circulation, helping day-trippers and frequent visitors who travel by land or sea. A regular passport is required for air travel. The government issued 18 million regular passports last year, and the number is steadily climbing. The State Department is encouraging people to apply early for the cards, in part to avoid the kind of rush on documents that happened a year ago when the government required a passport for people flying into the United States from elsewhere in the Western Hemisphere. Project manager Derwood Staeben said 200,000 people submitted comments and many complained about the cost and inconvenience of getting passports. The new cards fit inside a wallet and, for first-time adult applicants, will cost $45, compared with $100 for a first-time traditional passport. For people who hold a passport or apply for one simultaneously, the card will cost an extra $20. One concern for privacy advocates is that each passport card will contain an embedded radio transmitter chip. Known as RFID, the technology is controversial because critics fear that data from the chips could unknowingly be lifted by remote readers, in what's called "skimming." Staeben said a skimmer would only get a meaningless ID number from the passport cards. The number allows customs agents to automatically pull up a passport file on a computer from government databases, but skimmers would not have access to the raw data. As an added precaution, travelers could cover their cards in a sleeve that blocks transmissions. RFID chips have been embedded in every passport issued since August 2006. Staeben said security measures, including an embedded metal cage to block out skimmers, were featured in the newer passports to protect privacy and combat skimming. Guidelines: You share in the USA TODAY community, so please keep your comments smart and civil. Don't attack other readers personally, and keep your language decent. Use the "Report Abuse" button to make a difference. You share in the USA TODAY community, so please keep your comments smart and civil. Don't attack other readers personally, and keep your language decent. Use the "Report Abuse" button to make a difference. Read more