No, Athanasius was evidently not a Sabellian. This is demonstrably clear from his own words.

2. For neither do we hold a Son-Father, as do the Sabellians, calling Him of one but not of the same434 essence, and thus destroying the existence of the Son. Neither do we ascribe the passible body which He bore for the salvation of the whole world to the Father. Neither can we imagine three Subsistences separated from each other, as results from their bodily nature in the case of men, lest we hold a plurality of gods like the heathen. But just as a river, produced from a well, is not separate, and yet there are in fact two visible objects and two names. For neither is the Father the Son, nor the Son the Father. For the Father is Father of the Son, and the Son, Son of the Father. For like as the well is not a river, nor the river a well, but both are one and the same water which is conveyed in a channel from the well to the river, so the Father’s deity passes into the Son without flow and without division. For the Lord says, ‘I came out from the Father and am come’ (Joh. xvi. 85 28). But He is ever with the Father, for He is in the bosom of the Father, nor was ever the bosom of the Father void of the deity of the Son. For He says, ‘I was by Him as one setting in order’ (Prov. viii. 30). But we do not regard God the Creator of all, the Son of God, as a creature, or thing made, or as made out of nothing, for He is truly existent from Him who exists, alone existing from Him who alone exists, in as much as the like glory and power was eternally and conjointly begotten of the Father. For ‘He that hath seen’ the Son ‘hath seen the Father (Joh. xiv. 9). All things to wit were made through the Son; but He Himself is not a creature, as Paul says of the Lord: ‘In Him were all things created, and He is before all’ (Col. i. 16). Now He says not, ‘was created’ before all things, but ‘is’ before all things. To be created, namely, is applicable to all things, but ‘is before all’ applies to the Son only.

Christian Classics Ethereal Library

Quoted Verbatim from Athanasius' own 'Statement of Faith'

Expositio Fidei p259

NPNF2-04. Athanasius: Select Works and Letters

No, Athanasius was evidently not a Sabellian. This is demonstrably clear from his own words.

2. For neither do we hold a Son-Father, as do the Sabellians, calling Him of one but not of the same essence, and thus destroying the existence of the Son. Neither do we ascribe the passible body which He bore for the salvation of the whole world to the Father. Neither can we imagine three Subsistences separated from each other, as results from their bodily nature in the case of men, lest we hold a plurality of gods like the heathen. But just as a river, produced from a well, is not separate, and yet there are in fact two visible objects and two names. For neither is the Father the Son, nor the Son the Father. For the Father is Father of the Son, and the Son, Son of the Father. For like as the well is not a river, nor the river a well, but both are one and the same water which is conveyed in a channel from the well to the river, so the Father’s deity passes into the Son without flow and without division. For the Lord says, ‘I came out from the Father and am come’ (Joh. xvi. 85 28). But He is ever with the Father, for He is in the bosom of the Father, nor was ever the bosom of the Father void of the deity of the Son. For He says, ‘I was by Him as one setting in order’ (Prov. viii. 30). But we do not regard God the Creator of all, the Son of God, as a creature, or thing made, or as made out of nothing, for He is truly existent from Him who exists, alone existing from Him who alone exists, in as much as the like glory and power was eternally and conjointly begotten of the Father. For ‘He that hath seen’ the Son ‘hath seen the Father (Joh. xiv. 9). All things to wit were made through the Son; but He Himself is not a creature, as Paul says of the Lord: ‘In Him were all things created, and He is before all’ (Col. i. 16). Now He says not, ‘was created’ before all things, but ‘is’ before all things. To be created, namely, is applicable to all things, but ‘is before all’ applies to the Son only.

Christian Classics Ethereal Library

Quoted Verbatim from Athanasius' own 'Statement of Faith'

Expositio Fidei p259

NPNF2-04. Athanasius: Select Works and Letters

No, Athanasius was evidently not a Sabellian. This is demonstrably clear from his own words.

2. For neither do we hold a Son-Father, as do the Sabellians, calling Him of one but not of the same434 essence, and thus destroying the existence of the Son. Neither do we ascribe the passible body which He bore for the salvation of the whole world to the Father. Neither can we imagine three Subsistences separated from each other, as results from their bodily nature in the case of men, lest we hold a plurality of gods like the heathen. But just as a river, produced from a well, is not separate, and yet there are in fact two visible objects and two names. For neither is the Father the Son, nor the Son the Father. For the Father is Father of the Son, and the Son, Son of the Father. For like as the well is not a river, nor the river a well, but both are one and the same water which is conveyed in a channel from the well to the river, so the Father’s deity passes into the Son without flow and without division. For the Lord says, ‘I came out from the Father and am come’ (Joh. xvi. 85 28). But He is ever with the Father, for He is in the bosom of the Father, nor was ever the bosom of the Father void of the deity of the Son. For He says, ‘I was by Him as one setting in order’ (Prov. viii. 30). But we do not regard God the Creator of all, the Son of God, as a creature, or thing made, or as made out of nothing, for He is truly existent from Him who exists, alone existing from Him who alone exists, in as much as the like glory and power was eternally and conjointly begotten of the Father. For ‘He that hath seen’ the Son ‘hath seen the Father (Joh. xiv. 9). All things to wit were made through the Son; but He Himself is not a creature, as Paul says of the Lord: ‘In Him were all things created, and He is before all’ (Col. i. 16). Now He says not, ‘was created’ before all things, but ‘is’ before all things. To be created, namely, is applicable to all things, but ‘is before all’ applies to the Son only.

Quoted Verbatim from Athanasius' own 'Statement of Faith'

Expositio Fidei p259

NPNF2-04. Athanasius: Select Works and Letters

No, Athanasius was evidently not a Sabellian. This is demonstrably clear from his own words.

2. For neither do we hold a Son-Father, as do the Sabellians, calling Him of one but not of the same434 essence, and thus destroying the existence of the Son. Neither do we ascribe the passible body which He bore for the salvation of the whole world to the Father. Neither can we imagine three Subsistences separated from each other, as results from their bodily nature in the case of men, lest we hold a plurality of gods like the heathen. But just as a river, produced from a well, is not separate, and yet there are in fact two visible objects and two names. For neither is the Father the Son, nor the Son the Father. For the Father is Father of the Son, and the Son, Son of the Father. For like as the well is not a river, nor the river a well, but both are one and the same water which is conveyed in a channel from the well to the river, so the Father’s deity passes into the Son without flow and without division. For the Lord says, ‘I came out from the Father and am come’ (Joh. xvi. 85 28). But He is ever with the Father, for He is in the bosom of the Father, nor was ever the bosom of the Father void of the deity of the Son. For He says, ‘I was by Him as one setting in order’ (Prov. viii. 30). But we do not regard God the Creator of all, the Son of God, as a creature, or thing made, or as made out of nothing, for He is truly existent from Him who exists, alone existing from Him who alone exists, in as much as the like glory and power was eternally and conjointly begotten of the Father. For ‘He that hath seen’ the Son ‘hath seen the Father (Joh. xiv. 9). All things to wit were made through the Son; but He Himself is not a creature, as Paul says of the Lord: ‘In Him were all things created, and He is before all’ (Col. i. 16). Now He says not, ‘was created’ before all things, but ‘is’ before all things. To be created, namely, is applicable to all things, but ‘is before all’ applies to the Son only.

Christian Classics Ethereal Library

Quoted Verbatim from Athanasius' own 'Statement of Faith'

Expositio Fidei p259

NPNF2-04. Athanasius: Select Works and Letters