Ken Griffey Jr. has launched the most homers for the Mariners in a month, with 15 home runs in May 1994.

	NAME	HR	MONTH	G	AB	R	H	2B	3B	RBI	BB	HBP	SO	SB	CS	PA	TB	XBH	SH	SF	IBB	GIDP	AVG	OBP	SLG	OPS
1	Ken Griffey Jr. K. Griffey Jr.	15	May 1994	27	99	28	33	3	0	25	16	0	17	3	0	115	81	18	0	0	6	1	.333	.426	.818	1.244
2	Ken Griffey Jr. K. Griffey Jr.	14	June 1998	28	110	23	29	3	0	25	14	1	23	3	0	126	74	17	0	1	4	4	.264	.349	.673	1.022
3	Ken Griffey Jr. K. Griffey Jr.	13	April 1997	26	103	25	35	5	1	30	12	3	18	2	0	119	81	19	0	1	5	5	.340	.420	.786	1.207
4	Jay Buhner J. Buhner	13	September 1995	27	103	20	29	3	0	32	6	0	23	0	0	111	71	16	1	1	1	1	.282	.318	.689	1.008
5	Cal Raleigh C. Raleigh	12	May 2025	27	92	19	28	4	0	26	19	2	31	2	1	114	68	16	0	1	1	1	.304	.430	.739	1.169
6	Nelson Cruz N. Cruz	12	August 2015	27	108	24	34	6	0	19	14	2	31	1	0	124	76	18	0	0	2	2	.315	.403	.704	1.107
7	Alex Rodriguez A. Rodriguez	12	July 1999	25	98	21	33	6	0	30	8	1	21	3	2	108	75	18	0	1	0	3	.337	.389	.765	1.154
8	Ken Griffey Jr. K. Griffey Jr.	12	September 1997	24	91	24	27	2	0	25	13	2	20	3	0	109	65	14	0	3	1	2	.297	.385	.714	1.100
9	Ken Griffey Jr. K. Griffey Jr.	12	August 1997	30	115	24	38	8	1	24	14	2	21	1	1	131	84	21	0	0	7	0	.330	.412	.730	1.143
10	Jay Buhner J. Buhner	12	May 1996	25	94	20	29	4	0	29	13	0	29	0	0	108	69	16	0	1	1	0	.309	.389	.734	1.123
11	Nelson Cruz N. Cruz	11	June 2018	26	95	20	31	3	1	24	14	1	18	0	0	110	69	15	0	0	2	3	.326	.418	.726	1.144
12	Alex Rodriguez A. Rodriguez	11	August 1999	29	111	25	36	3	0	28	10	1	22	7	0	124	72	14	0	2	2	3	.324	.379	.649	1.028
13	Ken Griffey Jr. K. Griffey Jr.	11	May 1999	27	106	28	36	3	0	27	16	1	13	5	0	123	72	14	0	0	5	0	.340	.431	.679	1.110
14	Alex Rodriguez A. Rodriguez	11	May 1998	28	116	19	33	3	0	23	9	3	24	5	1	128	69	14	0	0	0	1	.284	.352	.595	.946
15	Ken Griffey Jr. K. Griffey Jr.	11	May 1997	27	110	21	32	4	0	32	11	0	21	3	0	124	69	15	0	3	2	2	.291	.347	.627	.974
16	Ken Griffey Jr. K. Griffey Jr.	11	July 1996	18	72	18	26	3	0	30	8	1	12	2	0	81	62	14	0	0	0	1	.361	.432	.861	1.293
17	Gorman Thomas G. Thomas	11	July 1985	28	106	21	24	3	0	21	17	0	25	0	0	123	60	14	0	0	0	1	.226	.333	.566	.899
18	Nelson Cruz N. Cruz	10	August 2017	25	91	20	31	7	0	24	9	3	21	0	0	104	68	17	0	1	0	1	.341	.413	.747	1.161
19	Mike Zunino M. Zunino	10	June 2017	24	79	14	24	3	0	31	7	2	32	0	0	89	57	13	0	1	0	0	.304	.371	.722	1.092
20	Nelson Cruz N. Cruz	10	September 2016	27	104	19	34	7	0	24	9	0	23	2	0	116	71	17	0	3	0	0	.327	.371	.683	1.053
21	Nelson Cruz N. Cruz	10	June 2016	27	108	19	29	5	0	18	9	1	29	0	0	118	64	15	0	0	2	8	.269	.331	.593	.923
22	Nelson Cruz N. Cruz	10	April 2015	22	87	14	28	3	1	22	7	0	18	1	0	94	63	14	0	0	2	1	.322	.372	.724	1.096
23	Raul Ibanez R. Ibanez	10	June 2013	27	107	13	28	2	1	22	8	0	30	0	0	115	62	13	0	0	1	3	.262	.313	.579	.892
24	Edgar Martinez E. Martinez	10	May 2003	26	100	16	28	3	0	30	12	1	18	0	0	114	61	13	0	1	0	5	.280	.360	.610	.970
25	Bret Boone B. Boone	10	June 2001	27	106	26	39	5	2	28	8	0	18	1	0	116	78	17	0	2	1	0	.368	.405	.736	1.141