The company will offer the Vodafone Global Standard 3G service, which uses the latest version of 3GPP (Third Generation Partnership Project) standards, from 20 December.
The 3GPP was established in 1998 to produce globally applicable technical specifications for 3G networks.
The J-Phone service will operate on a W-CDMA (Wideband Code Division Multiple Access) network.
J-Phone's Vodafone Global Standard includes services such as voice communications, wireless packet data transmission of up to 384Kbps (bits per second), video conferencing and global SMS (short message service) between countries where Vodafone has group companies.
Vodafone will also offer international roaming either with a W-CDMA/GSM (Global System for Mobile Communications) dual-mode handset or with a USIM (Universal Subscriber Identity Module) card that can be transferred to a GSM handset when overseas, allowing the user to keep their usual phone number.
Monthly subscription fees will vary, but will range from ¥3,500 (£18) to ¥14,500 (£74).
J-Phone also unveiled three 3G mobile handsets. NEC's V-N701, a W-CDMA/GSM900/GSM1800 dual-mode handset with a colour LCD and two 100,000-pixel digital cameras for videoconferencing, is expected to be available on 20 December.
Nokia's 6650 is also a dual-mode model with a 320,000-pixel digital camera for still images and video clips. No videoconference function is available. It is expected to be out in late December.
Sanyo's V-SA701 is a single-mode 3G handset, equipped with a videoconference function and two 110,000-pixel digital cameras for videoconferencing and still images. It is also expected to be out in late December.
J-Phone hoped to sell one million handsets in the first year of the new service.
Japan's largest 3G network based on W-CDMA is NTT DoCoMo's Foma, which was launched in October 2001. It covers only the Tokyo metropolitan area.
Although NTT DoCoMo plans to expand Foma to cover over 90 percent of populated areas in Japan by the end of this year, the service is still experiencing difficulties in attracting users. After a year, DoCoMo 3G subscribers number 142,000, which is 1.4 million short of the company's initial expectations.
J-Phone's Vodafone Global standard service will cover 60% of Japan's populated areas, and by the third quarter next year the company plans to reach almost the same coverage area as its existing 2G service.
Later next year J-Phone aims to launch J-sky, its wireless Internet service. This will be similar to DoCoMo's I-mode, which has been offered to J-Phone's 2G users.