MarComms - GMDSS and Search and Rescue Areas

International VHF Marine Radio Channels and Frequencies
The following table is adapted from the International Telecommunications Union Radio Regulations Appendix S18, including changes adopted by the 2000 World Radio Conference. Transmission on frequencies or channels shown in blue are not allowed within U.S. territorial waters, but are allowed on the high seas and in most other countries. Note that a marine radio operating in the international mode on a channel in which the ship station frequency is shown in black and the shore station frequency shown in blue would not be able to communicate with a U.S. shore station. The large number of "blue" channels and frequencies indicates the shortage of VHF maritime spectrum in the U.S. compared to most other maritime countries. Finally, note also that changes made by WRC97 shown in green have not yet come into force.
Table of Transmitting Frequencies in the VHF
Maritime Mobile

Channel Designator	Notes	Transmitting Frequencies (MHz)		Intership	Port Operations and Ship Movement		Public correspondence
Channel Designator	Notes	Ship Stations	Coast Stations	Intership	Single frequency	Two frequency	Public correspondence
60		156.025	160.625			x	x
01		156.050	160.650			x	x
61	m, o	156.075	160.675			x	x
02	m, o	156.100	160.700			x	x
62	m, o	156.125	160.725			x	x
03	m, o	156.150	160.750			x	x
63	m, o	156.175	160.775			x	x
04	m, o	156.200	160.800			x	x
64	m, o	156.225	160.825			x	x
05	m, o	156.250	160.850			x	x
65	m, o	156.275	160.875			x	x
06	f	156.300		x
66		156.325	160.925			x	x
07		156.350	160.950			x	x
67	h	156.375	156.375	x	x
08		156.400		x
68		156.425	156.425		x
09	I	156.450	156.450	x	x
69		156.475	156.475	x	x
10	f	156.500	156.500	x	x
70	j	156.525	156.525	Digital selective calling for distress, safety and calling
11		156.550	156.550		x
71		156.575	156.575		x
12		156.600	156.600		x
72	i	156.625		x
13	k	156.650	156.650	x	x
73	h	156.675	156.675	x	x
14		156.700	156.700		x
74		156.725	156.725		x
15	g	156.750	156.750	x	x
75	n	156.775			x
16		156.800	156.800	DISTRESS, SAFETY AND CALLING
76	n	156.825			x
17	g	156.850	156.850	x	x
77		156.875		x
18	m	156.900	161.500		x	x	x
78		156.925	161.525			x	x
19		156.950	161.550			x	x
79		156.975	161.575			x	x
20		157.000	161.600			x	x
80		157.025	161.625			x	x
21		157.050	161.650			x	x
81		157.075	161.675			x	x
22	m	157.100	161.700			x	x
82	m, o	157.125	161.725		x	x	x
23	m, o	157.150	161.750			x	x
83	m, o	157.175	161.775		x	x	x
24	m, o	157.200	161.800			x	x
84	m, o	157.225	161.825		x	x	x
25	m, o	157.250	161.850			x	x
85	m, o	157.275	161.875		x	x	x
26	m, o	157.300	161.900			x	x
86	m, o	157.325	161.925		x	x	x
27		157.350	161.950			x	x
87		157.375			x
28		157.400	162.000			x	x
88		157.425			x
AIS 1	l	161.975	161.975
AIS 2	l	162.025	162.025

NOTES REFERRING TO THE TABLE

General notes

Administrations may designate frequencies in the intership, port operations and ship movement services for use by light aircraft and helicopters to communicate with ships or participating coast station in predominantly maritime support operations under the conditions specified in Nos. S51.69, S51.73, S51.74, S51.75, S51.76, S51.77 and S51.78. However, the use of the channels which are shared with public correspondence shall be subject to prior agreement between interested and affected administrations.

The channels of the present Appendix, with the exception of channels 06, 13, 15, 16, 17, 70, 75 and 76, may also be used for highspeed data and facsimile transmissions, subject to special arrangement between interested and affected administrations.

The channels of the present Appendix, but preferably channel 28 and with exception of channels 06, 13, 15, 16, 17, 70, 75 and 76, may be used for direct-printing telegraphy and data transmission, subject to special arrangement between interested and affected administrations.

The frequencies in this table may also be used for radiocommunications on inland waterways in accordance with the conditions specified in No. S5.226.

Administrations having an urgent need to reduce local congestion may apply 12.5 kHz channel interleaving on a non-interference basis to 25 kHz channels, provided:

Recommendation ITU-R M.1084-2 shall be taken into account when changing to 12.5 kHz channels;

It shall not affect the 25 kHz channels of the Appendix S18 maritime mobile distress and safety frequencies, especially the channels 6, 13, 15, 16, 17, and 70, nor the technical characteristics mentioned in Recommendation ITU-R M.489-2 for these channels;

Implementation of 12.5 kHz channel interleaving and consequential national requirements shall be subject to prior agreement between the implementing administrations and administrations whose ship station or services may be affected.

Specific notes

The frequency 156.300 MHz (channel 06) (see Appendix S13, Appendix S15 and S51.79) may also be used for communication between ship stations and aircraft stations engaged in coordinated search and rescue operations. Ship stations shall avoid harmful interference to such communications on channel 06 as well as to communications between aircraft stations, ice-breakers and assisted ships during ice seasons.

Channels 15 and 17 may also be used for on-board communications provided the effective radiated power does not exceed 1 W, and subject to the national regulations of the administration concerned when these channels are used in its territorial waters.

Within the European Maritime Area and in Canada these frequencies (channels 10, 67, 73) may also be used, if so required, by the individual administrations concerned, for communication between ship stations, aircraft stations and participating land stations engaged in coordinated search and rescue and anti-pollution operations in local areas, under the conditions specified in Nos. S51.69, S51.73, S51.74, S51.75, S51.76, S51.77 and S51.78.

The preferred first three frequencies for the purpose indicated in note a) are 156.450 MHz (channel 09), 156.625 MHz (channel 72) and 156.675 MHz (channel 73).

This channel (70) is to be used exclusively for digital selective calling for distress, safety and calling.

Channel 13 is designated for use on a world-wide basis as a navigation safety communication channel, primarily for intership navigation safety communications. It may also be used for the ship movement and port operations service subject to the national regulations of the administrations concerned.

The channels will be used for an automatic ship identification and surveillance system capable of providing worldwide operation on high seas, unless other frequencies are designated on a regional basis for this purpose.

These channels may be operated as a single frequency channels, subject to special arrangement between interested or affected administrations.

The use of these channels should be restricted to navigation-related communications only and all precautions should be taken to avoid harmful interference to channel 16, e.g. by limiting the output power to 1 W or by means geographical separation.

These channels may be used to provide bands for initial testing and the possible future introduction of new technologies, subject to special arrangement between interested or affected administrations. Stations using these channels or bands for the testing and the possible future introduction of new technologies shall not cause harmful interference to, and shall not claim protection from, other stations operating in accordance with Article 5.

see U.S. VHF Marine Radio Frequencies and Channels